Qualification: 
Ph.D, MS, B-Tech
shantinair@aims.amrita.edu

Professor Nair is the Dean of Research to Amrita Vishwa Vidyapeetham, and also the Director of Amrita Centre for Nanosciences and Molecular Medicine (ACNSMM), Health Sciences Campus. Dr. Nair received his Bachelor of Technology degree in Metallurgical Engineering from the Indian Institute of Technology, Bombay, India, in 1976; Master of Science (1978) and Doctor of Engineering Science (1983) degrees in Materials Science and Engineering from Columbia University, New York, USA. He joined the faculty of the Mechanical Engineering Department of the University of Massachusetts, Amherst, MA, USA, in 1985 where he has since taught and conducted research in the area of composite materials. In 2006, he joined Amrita Vishwa Vidyapeetham, India. He heads initiatives in the applications of Nanotechnology to Medicine and Energy areas. Areas of research include nanomedicine, tissue engineering, surface modification of materials, and uses of nanomaterials in photovoltaics, supercapacitors and batteries.

In 1986, Dr. Nair received the Presidential Young Investigator Award from President Ronald Reagan for research in composite materials. He is a recipient of numerous awards from the National Science Foundation, USA, and from the industry in materials research. He received the MRSI Medal in Feb 2009 for outstanding contributions in the field of Materials Science. He is the recipient of the Prestigious National Research Award from the Government of India in 2011 for research in Nanosciences. Dr. Nair received the impressive C N R Rao India Nanosciences Award 2014 for outstanding contributions in Nanotechnology Research and Development in India. 

Publications

Publication Type: Journal Article

Year of Publication Title

2019

G. Gopakumar, Ashok, A., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “Atomically Thin 2D Layered MoS2-enabled Photo-Current Characteristics in TiO2 Nanoparticle Films”, Applied Nanoscience (In Press), 2019.[Abstract]


The present study examines photo-current characteristics of 2D layered molybdenum disulfide (MoS2) incorporated titanium dioxide (TiO2) nanoparticle films at different illumination conditions established using while light (AM1.5), blue (406 nm), and green (525 nm) lasers. Photo-current values, measured from a two-terminal device configuration fabricated using TiO2 nanoparticle films with different weight % of MoS2, were observed to be sensitive to the quantity of MoS2 in the bulk TiO2. It is observed that incorporation of 30 wt% of MoS2 in TiO2 enhanced photo-current up to 48.3% compared to that of pristine TiO2 nanoparticle film under AM1.5 illumination. Blue and green laser-based measurements show that the photo-current is highly sensitive to the weight fraction of MoS2 in TiO2 and incident energy used to generate excitons. The variation observed in the measured photo-current is directly attributed to the optical responsivity of MoS2 to the incoming photons

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2019

Manju V., Iyer, S., Menon, D., Shantikumar V Nair, and Dr. Manitha B. Nair, “Evaluation of Osseointegration of Staged or Simultaneously Placed Dental Implants with Nanocomposite Fibrous Scaffolds in Rabbit Mandibular Defect”, Materials Science and Engineering C, vol. 104, 2019.[Abstract]


Implant-supported dental prosthesis in patients with edentulism or those with reconstructed bone have long survival rate, but the success depends largely on the quality and quantity of the available bone at the recipient site. The usage of autograft is the gold standard treatment for vertical bone augmentation, but it has many limitations. In this study, we have developed a nanocomposite fibrous scaffold [silica coated nanoHA-gelatin reinforced with electrospun poly(L-lactic acid) (PLLA) nanoyarns] and evaluated its efficacy to promote osseointegration in rabbit mandibular defect in comparison to the scaffold without fibers and commercial nanoHA-collagen graft. For this, critical sized bilateral defect (10 mm length, 3 mm depth and 3 mm width) was created in rabbit mandible and dental implantation was done in two manners. In strategy 1, Ti dental implant was placed along with the scaffold and in strategy 2, the scaffold was implanted for 3 months to facilitate new bone formation followed by Ti dental implantation. In strategy 2, the fibrous scaffold could promote new bone formation and osseointegration in rabbit mandibular defect when compared to the scaffolds without fibers and commercial graft, but strategy 1 was not successful. These findings demonstrated that nanocomposite fibrous scaffold is a promising biomaterial to promote new bone formation and osseointegration in mandibular defect. © 2019

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2019

A. Ashok, Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “Spray Pyrolysis-Coated Nano-Clustered CdTe on Amorphous Si Thin Films for Heterojunction Solar Cells”, Applied Nanoscience (Switzerland) (In Press), 2019.[Abstract]


Heterojunction solar cells are demonstrated employing spray pyrolysis-processed nano-clustered cadmium telluride (CdTe) on DC-sputtered amorphous silicon (a-Si) as p- and n-type layers, respectively. CdTe and a-Si films were subjected to X-ray photoelectron spectroscopic measurements showing Cd 3d (404.9 eV) and Te 3d (575.8 eV) peaks corresponding to CdTe while the peaks Si 2p (98.3 eV) and Si 2 s (148.3 eV) represent a-Si. Heterojunction solar cells with a stacked structure of FTO/a-Si/CdTe/Al resulted in a photo-conversion efficiency of 2.7% for an optimized thickness values of a-Si (1 µm) and CdTe (6 µm) films. © 2019, King Abdulaziz City for Science and Technology.

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2019

A. P. Varghese, Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Cobalt Oxide Thin Films for High Capacity and Stable Li-ion Battery Anode”, Journal of Solid State Electrochemistry, vol. 23, pp. 513-518, 2019.[Abstract]


Here, we report reactive DC-sputter deposited Co 3 O 4 thin films as a promising and stable Li-ion battery anode. Thin films were deposited on stainless steel by reactive sputtering of cobalt target in O 2 atmosphere. X-ray diffraction and X-ray photo electron spectroscopy confirm the formation of Co 3 O 4 crystal structure and absence of other impurities. The electron microscopy analysis shows a columnar growth morphology of the thin films while high resolution images reveal that the film is composed of ultra-small nanoparticles of average size of 5 nm. Fabricated half cells upon cycling between 3.0 and 0.01 V exhibit a stable capacity of 1125 mAh/g at a current density of 1 A/g for 100 cycles. Moreover, the electrode exhibited excellent rate capability and stability at higher rates; at current density of 10 A/g, a capacity close to 1000 mAh/g was observed. The excellent cycling stability of the cell was further confirmed by cycling at a high rate of 25 A/g (28 C) wherein the same was able to retain a capacity of 330 mAh/g even at the end of 1800 cycles. This enhanced performance could be related to the formation of 5-nm primary particles and columnar growth morphology, capable of reducing the lithium ion diffusion lengths and thus offered better kinetics even at high rates.

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2019

B. Gangaja, Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Surface-Engineered Li 4 Ti 5 O 12 Nanoparticles by TiO2 Coating for Superior Rate Capability and Electrochemical Stability at Elevated Temperature”, Applied Surface Science, vol. 480, pp. 817-821, 2019.[Abstract]


Lithium ion batteries are dominating the energy storage market owing to its capability in powering portable electronics to electric vehicles. However, the power capabilities of these batteries are still relatively low limiting their applications in fast charging. In this paper, we report a strategy in elevating the rate capability of lithium titanate (Li 4 Ti 5 O 12 - LTO), one of the safest anode materials known. We demonstrate that a simple chemical method of coating titania (TiO 2 ) on lithium titanate nanoparticles followed by low temperature annealing yields a superior anode to bare-LTO. The surface coated electrode exhibits high discharge capacity of 212 mAh/g at 10C rate while the bare-LTO deliver only 138 mAh/g. Likewise, the surface engineered electrode displays excellent ultra-high rate capability (150C) and long cycling stability of 1000 cycles (at 60C rate). Impedance spectroscopy results confirm that the charge transfer resistance in surface engineered sample (CS-3) is comparatively lower than the bare-LTO electrode. Ex situ TEM investigation shows that the titania inhibits surface phase transition when cycled at elevated temperature which could be advantageous as it is a manifestation of minimal gassing in the batteries.

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2019

D. Narayanan, Pillai, G. J., Shantikumar V Nair, and Dr. Deepthy Menon, “Effect of Formulation Parameters on Pharmacokinetics, Pharmacodynamics, and Safety of Diclofenac Nanomedicine”, Drug Deliv Transl Res, 2019.[Abstract]


This study reports the development of a nanoformulation of diclofenac sodium, a potent non-steroidal anti-inflammatory drug, at its clinical dose, utilizing a FDA approved polymer, hydroxyethyl starch. The study specifically focused on the control of pharmacokinetics, pharmacodynamics, and biodistribution by particle surface functionalization and alteration of excipient levels in the final formulation. Stable diclofenac sodium-loaded hydroxyethyl starch nanoparticles (nanodiclo) of size 170 ± 5 nm and entrapment efficiency 72 ± 3% were prepared. Free diclofenac, nanodiclo, nanodiclo surface functionalized by PEGylation, nanodiclo with excipients removed, and finally PEGylated nanodiclo with excipients removed were all tested comparatively at two different doses. The results showed substantial impact of both excipients and PEGylation on the pharmacokinetics and pharmacodynamics in vivo. Further, the results proved that excipient removed PEGylated nanodiclo at lower dose achieved clinical therapeutic levels in blood for up to 120 h, with minimal accumulation in critical organs, and much better efficacy than other controls.

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2019

S. Padmakumar, Parayath, N. N., Shantikumar V Nair, Dr. Deepthy Menon, and Amiji, M. M., “Enhanced Anti-tumor Efficacy and Safety with Metronomic Intraperitoneal Chemotherapy for Metastatic Ovarian Cancer using Biodegradable Nanotextile Implants.”, Journal of Controlled Release, vol. 305, pp. 29-40, 2019.[Abstract]


The objective of this study was to evaluate intraperitoneal (IP) metronomic chemotherapy using sustained release paclitaxel (PTX) delivery from electrospun biodegradable polymeric yarns woven into suturable nanotextiles. Following confirmation of in vitro PTX efficacy in ID8-VEGF epithelial ovarian cancer cells, in vivo studies were performed upon surgical peritoneal implantation of nanotextile implants in orthotopic, syngeneic ID8-VEGF tumor-bearing C57BL/6 mice. In comparison to the clinical PTX-solution, there was a significant enhancement of anti-tumor efficacy and safety with PTX-nanotextiles. After 35-days, the peritoneum of tumor-bearing mice with PTX-nanotextiles was completely devoid of tumor nodules and ascitic fluid. Additionally, VEGF levels measured in peritoneal lavage fluid were 300-fold lower compared to PTX-solution and 600-fold lower as compared to untreated tumor-bearing animals. PTX-solution treated group also developed severe metastatic lesions and progressive ascitic fluid buildup. More importantly, no signs of systemic/ organ toxicity were observed in PTX-nanotextile implanted mice, unlike the systemic toxic effects induced by PTX-solution. Collectively, our results show the therapeutic and safety advantages offered by combining clinically translatable metronomic low-dose chemotherapy and IP pharmacokinetics using biodegradable nanotextile implants in addressing the challenges of late-stage ovarian cancer.

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2019

K. Meethaleve Sajesh, Anusha Ashokan, Gowd, G. Siddaraman, Dr. Manzoor K., Unni, A. K. K., and Shantikumar V Nair, “Magnetic 3D scaffold: A theranostic tool for tissue regeneration and non-invasive imaging in vivo.”, Nanomedicine: Nanotechnology, Biology, and Medicine, vol. 18, pp. 179-188, 2019.[Abstract]


We report an osteoconducting magnetic 3D scaffold using Fe doped nano-hydroxyapatite-Alginate-Gelatin (AGHFe1) for Magnetic Resonance Imaging based non-invasive monitoring of bone tissue regeneration. In rat cranial defect model, the scaffold facilitated non-invasive monitoring of cell migration, inflammatory response and matrix deposition by unique changes in transverse relaxation time (T2). Cell infiltration resulted in a considerable increase in T2 from ~37 to ~62 ms, which gradually returned to that of native bone (~23 ms) by 90 days. We used this method to compare in vivo performance of scaffold with bone-morphogenic protein-2 (AGHFe2) or faster degrading (AGHFe3). MRI and histological analysis over 90 days showed non-uniform bone formation in AGHFe1 with ∆T2 (T2 - T2 ) ~13 ms, whereas, AGHFe2 and AGHFe3 showed ∆T2 ~ 09 and 05 ms respectively, suggesting better bone formation in AGHFe3. Thus, we show that MR-contrast enabled scaffold can help better assessment of bone-regeneration non-invasively.

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2019

A. Choorakott Pushkaran, Vinod, V., Muralidharan Vanuopadath, Sudarslal S, Shantikumar V Nair, Vasudevan, A. Kumar, Dr. Raja Biswas, and Dr. Gopi Mohan C., “Combination of Repurposed Drug Diosmin with Amoxicillin-Clavulanic acid Causes Synergistic Inhibition of Mycobacterial Growth”, Scientific Reports, vol. 9, no. 1, 2019.[Abstract]


Effective therapeutic regimens for the treatment of tuberculosis (TB) are limited. They are comprised of multiple drugs that inhibit the essential cellular pathways in Mycobacterium tuberculosis (Mtb). The present study investigates an approach which enables a combination of Amoxicillin-Clavulanic acid (AMC) and a repurposed drug for its synergistic effect towards TB treatment. We identified Diosmin (DIO), by targeting the active site residues of L,D-transpeptidase (Ldt) enzymes involved in Mtb cell wall biosynthesis by using a structure-based drug design method. DIO is rapidly converted into aglycone form Diosmetin (DMT) after oral administration. Binding of DIO or DMT towards Ldt enzymes was studied using molecular docking and bioassay techniques. Combination of DIO (or DMT) and AMC exhibited higher mycobactericidal activity against Mycobacterium marinum as compared to individual drugs. Scanning electron microscopy study of M. marinum treated with AMC-DIO and AMC-DMT showed marked cellular leakage. M. marinum infected Drosophila melanogaster fly model showed an increased fly survival of 60% upon treatment with a combination of AMC and DIO (or DMT). Finally, the enhanced in vitro antimicrobial activity of AMC-DIO was validated against Mtb H37Ra and a MDR clinical isolate. Our results demonstrate the potential for AMC and DIO (or DMT) as a synergistic combination for the treatment of TB. © 2019, The Author(s).

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2019

Girish C. M., Dr. Subramania Iyer K., Dr. Krishnakumar T., GS, G., Dr. Manzoor K., and Shantikumar V Nair, “A Novel Surface Enhanced Raman Catheter for Rapid Detection, Classification, and Grading of Oral Cancer”, Advanced Healthcare Materials, vol. 8, no. 13:e1801557, 2019.[Abstract]


Fabrication and testing of a novel nanostructured surface-enhanced Raman catheter device is reported for rapid detection, classification, and grading of normal, premalignant, and malignant tissues with high sensitivity and accuracy. The sensor part of catheter is formed by a surface-enhanced Raman scattering (SERS) substrate made up of leaf-like TiO2 nanostructures decorated with 30 nm sized Ag nanoparticles. The device is tested using a total of 37 patient samples wherein SERS signatures of oral tissues consisting of malignant oral squamous cell carcinoma (OSCC), verrucous carcinoma, premalignant leukoplakia, and disease-free conditions are detected and classified with an accuracy of 97.24% within a short detection-cum-processing time of nearly 25-30 min per patient. Neoplastic grade changes detected using this device correlate strongly with conventional pathological data, enabling correct classification of tumors into three grades with an accuracy of 97.84% in OSCC. Thus, the potential of a SERS catheter device as a point-of-care pathological tool is shown for the rapid and accurate detection, classification, and grading of solid tumors.

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2019

Serene Xavier, Dr. Gopi Mohan C., Shantikumar V Nair, Krishnakumar N. Menon, and Dr. Lakshmi Sumitra, “Generation of Humanized Single-chain Fragment Variable Immunotherapeutic against EGFR Variant III using Baculovirus Expression System and in vitro validation.”, Int J Biol Macromol, vol. 124, pp. 17-24, 2019.[Abstract]


Epidermal growth factor receptor variant III (EGFRvIII) is known to be specifically expressed in cancer cells and associated with tumor virulence. The receptor provides an opportunity for both specifically targeting the tumor cells as well as for potentially controlling and inhibiting tumor progression. In this study, humanized anti-EGFRvIII single-chain fragment variable (hscFv) was expressed in insect cell culture system to accommodate post-translational glycosylations crucial for the fragment stability and efficacy. Target specific binding of the developed fragment to EGFRvIII expressing cell lines and EGFRvIII positive glioblastoma patient samples was evaluated by immunocytochemistry and immunohistochemistry respectively. Downstream intracellular signaling mechanisms related to the action of the developed antibody fragment on growth/metabolism of the cell was evaluated in U87-EGFRvIII human glioblastoma cell lines. It was observed that the hscFv bound specifically to EGFRvIII in mutant expressing cells. Functionally, hscFv was found to confer anti-proliferative properties in EGFRvIII expressing cell lines by downregulating phosphorylation of EGFR/EGFRvIII, Lyn, PI3K and GLUT3 involved in proliferation and metabolism. This study demonstrated the significance of hscFv as a potential immunotherapeutic agent as well as a targeting agent for specific delivery of drugs to EGFRvIII expressing cancer cells.

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2019

S. Padmakumar, Dr. Bindhu Paul, Pavithran, K., Vijaykumar, D. Kottarathi, Rajanbabu, A., Sivanarayanan, T. Balakrishn, Kadakia, E., Amiji, M. M., Shantikumar V Nair, and Dr. Deepthy Menon, “Long-term Drug Delivery using Implantable Electrospun Woven Polymeric Nanotextiles”, Nanomedicine: Nanotechnology, Biology, and Medicine, vol. 15, no. 1, pp. 274-284, 2019.[Abstract]


A woven nanotextile implant was developed and optimized for long-term continuous drug delivery for potential oncological applications. Electrospun polydioxanone (PDS) nanoyarns, which are twisted bundles of PDS nanofibres, were loaded with paclitaxel (PTX) and woven into nanotextiles of different packing densities. A mechanistic modeling of in vitro drug release proved that a combination of diffusion and matrix degradation controlled the slow PTX-release from a nanoyarn, emphasizing the role of nanostructure in modulating release kinetics. Woven nanotextiles, through variations in its packing density and thereby architecture, demonstrated tuneable PTX-release. In vivo PTX-release, pharmacokinetics and biodistribution were evaluated in healthy BALB/c mice by suturing the nanotextile to peritoneal wall. The slow and metronomic PTX-release for 60 days from the loosely woven implant was extremely effective in enhancing its residence in peritoneum, in contrast to intraperitoneal injections. Such an implantable matrix offers a novel platform for therapy of solid tumors over prolonged durations

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2018

A. R. Melge, Kumar, L. G., Pavithran, K., Shantikumar V Nair, Dr. Manzoor K., and Dr. Gopi Mohan C., “Predictive Models for Designing Potent Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia for Understanding its Molecular Mechanism of Resistance by Molecular Docking and Dynamics Simulations”, Journal of Biomolecular Structure and Dynamics, 2018.[Abstract]


BCR-ABL fusion protein drives chronic myeloid leukemia (CML) which constitutively activates tyrosine kinase involved in the initiation and maintenance of CML phenotype. Ponatinib, an oral drug, was discovered as an efficient BCR-ABL inhibitor by addressing imatinib drug resistance arising due to the point mutations at its active sites. In this study, 44 BCR-ABL kinase inhibitors, which are derivatives of ponatinib, were used to develop a robust two-dimensional quantitative structure–activity relationship (2D-QSAR) and 3D-Pharmacophore models by dividing dataset into 32 training sets and 12 test set molecules. 2D-QSAR model was developed using Genetic Function Approximation (GFA) algorithm consisting of four types of information-rich molecular descriptors, electrotopological (ES_Count_aasN and ES_Sum_aaaC), electronic (Dipole_X), spatial (PMI_Y) and thermodynamic (LogD), primarily contributing to BCR-ABL kinase inhibitory activity. For the best 2D-QSAR model, the statistics were R 2 = 0.8707, R 2 pred = 0.8142 and N = 32 for the training set molecules. Phase module of Schrödinger suit was employed for 3D-Pharmacophore model development showing five different pharmacophoric features–ADHHPRR with good R 2 of 0.9629, F of 175.3, Q 2 of 0.645 and root-mean-square error (RMSE) of 0.214 that are essential for an effective BCR-ABL kinase inhibition. These two models were further validated by cross-validation, test set predictions, enrichment factor calculations and predictions based on the external dataset. The molecular mechanism of resistance arising due to gate keeper mutation T315I of ABL kinase in complex with its inhibitors was also studied using molecular docking and molecular dynamics simulations. Our developed models predicted key chemical features for designing potent inhibitors against BCR-ABL kinase activity and its resistance mechanism to CML disease therapy. Communicated by Ramaswamy H. Sarma. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.

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2018

Dr. Dhamodaran Santhanagopalan, Benny, M., Binitha, G., and Shantikumar V Nair, “Long Cycle-life and High Rate Capability of Electrosprayed NiCo2O4 Nanoparticles as Li-ion Battery Anode”, Ionics, 2018.

2018

S. Mohapatra, Shantikumar V Nair, and Rai, A. Kumar, “Synthesis of Co3O4 Nanoparticles Wrapped Within Full Carbon Matrix as an Anode Material for Lithium Ion Batteries”, Acta Metallurgica Sinica (English Letters), vol. 31, pp. 164–170, 2018.[Abstract]


A facile polyol-assisted pyro-synthesis method was used to synthesize Co3O4 nanoparticles embedded into carbon matrix without using any conventional carbon source. The surface analysis by scanning electron microscopy showed that the Co3O4 nanoparticles ({\textasciitilde}20 ± 5 nm) are tightly enwrapped within the carbon matrix. CHN analysis determined the carbon content was only 0.11{%} in the final annealed sample. The Co3O4@carbon exhibited high capacities and excellent cycling performance as an anode at various current rates (such as 914.4 and 515.5 mAh g−1 at 0.25 and 1.0 C, respectively, after 50 cycles; 318.2 mAh g−1 at a high current rate of 5.0 C after 25 cycles). This superior electrochemical performance of the electrode can be attributed to the various aspects, such as, (1) the existence of carbon matrix, which acts as a flexible buffer to accommodate the volume changes during Li+ ion insertion/deinsertion and facilitates the fast Li+ and electron transfer and (2) the anchoring of Co3O4 nanoparticles within the carbon matrix prevents particles agglomeration.

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2018

B. Gangaja, Muralidharan, H. P., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Ultra long (10K) Cycle-Life and High-Power Li-Ion Storage in Li4Ti5O12 Films Developed via Sustainable Electrophoretic Deposition Process”, ACS Sustainable Chemistry and Engineering, vol. 6, pp. 4705-4710, 2018.

2018

D. Susan Baji, Jadhav, H. S., Shantikumar V Nair, and Alok Kumar Rai, “Porous MnCo2O4 as Superior Anode Material Over MnCo2O4 Nanoparticles for Rechargeable Lithium ion Batteries”, Journal of Solid State Chemistry, vol. 262, pp. 191 - 198, 2018.[Abstract]


Pyro synthesis is a method to coat nanoparticles by uniform layer of carbon without using any conventional carbon source. The resultant carbon coating can be evaporated in the form of CO or CO2 at high temperature with the creation of large number of nanopores on the sample surface. Hence, a porous MnCo2O4 is successfully synthesized here with the same above strategy. It is believed that the electrolyte can easily permeate through these nanopores into the bulk of the sample and allow rapid access of Li+ ions during charge/discharge cycling. In order to compare the superiority of the porous sample synthesized by pyro synthesis method, MnCo2O4 nanoparticles are also synthesized by sol-gel synthesis method at the same parameters. When tested as anode materials for lithium ion battery application, porous MnCo2O4 electrode shows high capacity with long lifespan at all the investigated current rates in comparison to MnCo2O4 nanoparticles electrode

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2018

B. Gangaja, Haridas, A. K., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Spray Pyrolysis-Deposited TiO2 Thin Films as High-Performance Lithium ion Battery Anodes”, Ionics, 2018.[Abstract]


Focusing on additive-free electrodes, thin films are of typical interest as electrodes for lithium ion battery application. Herein, we
report the fabrication of TiO2 thin films by spray pyrolysis deposition technique. X-ray diffraction and transmission electron
microscopic analysis confirms the formation of anatase TiO2. Electrochemical evaluation of these sub-micron TiO2 thin films
exhibits high-rate performance and long cycling stability. At 1C rate (1C = 335 mA/g), the electrode delivered discharge capacity
of 247 mAh/g allowing about 0.74 lithium into the structure. The electrodes also delivered specific capacities of 122 and 72 mAh/
g at 10 and 30C rates, respectively. Without conductive additives, this excellent performance can be attributed to the nanosize
effect of TiO2 particles combined with the uniform porous architecture of the electrode. Upon cycling at high rates (10 and 30C),
the electrode exhibited excellent cycling stability and retention, specifically only < 0.6% capacity loss per cycle over 2500 cycles.

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2018

S. N. Vijayaraghavan, Ashok, A., Gopakumar, G., Menon, H., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “All Spray Pyrolysis-coated CdTe–TiO2 Heterogeneous Films for Photo-Electrochemical Solar Cells”, Materials for Renewable and Sustainable Energy, vol. 7, p. 12, 2018.[Abstract]


Cadmium telluride (CdTe) thin films of different thicknesses deposited onto titanium dioxide (TiO2) nanoparticle layer by spray pyrolysis deposition (SPD) are demonstrated as major photo-active semiconductor in photo-electrochemical solar cell configuration using iodide/triiodide (I−/I3−) redox couple as a hole transport layer. The CdTe–TiO2 heterogeneous films were characterized by X-ray photoelectron spectroscopy which identified doublet split of Cd 3d and Ti 2p which confirms CdTe and TiO2. Optical absorbance and transmittance of CdTe and TiO2 films which were examined by UV–Vis spectroscopy confirm that the optical bandgap of CdTe is 1.5&nbsp;eV with a dominant photo-absorption in the spectral window of 350–800&nbsp;nm, while TiO2 showed a bandgap of 3.1&nbsp;eV and is optically transparent in the visible spectral window. The present work examined photo-anodes comprising 1, 3, 5, and 10 SPD cycles of CdTe coated on TiO2 nanoparticle layer. The solar cell with 5 SPD cycles of CdTe resulting in 0.4{%} efficiency. Results can be articulated to the CdTe deposited by 5 SPD cycles provided an optimum surface coverage in the bulk of TiO2, while the higher SPD cycles leads to agglomeration which blocks the porosity of the heterogeneous films.

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2018

M. Benny, Gangaja, B., Shantikumar V Nair, and Santhanagopalan, D., “Electrosprayed NiCo2O4 Nanoparticles for Long Cycle life and High-power Li-ion Battery Anode”, Ionics, vol. 24, pp. 3375–3383, 2018.[Abstract]


Electrospraying-based synthesis of NiCo2O4 (NCO-ES) nanoparticles that exhibit long cycle life and high rate capability is reported. The results are compared with a conventionally prepared NiCo2O4 sample by direct annealing (NCO-DA). The structure and morphology of NCO-ES and NCO-DA nanoparticles have been characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy to confirm the size, morphology, structure, and surface chemistry of the as-prepared samples. Electrochemical testing established that the NCO-ES sample displayed enhanced Li-ion storage performance. The NCO-ES delivered a discharge capacity of almost 370&nbsp;mAh/g at the end of 50 cycles at 1C rate (890&nbsp;mA/g) while only 180&nbsp;mAh/g was retained for the NCO-DA sample at the same condition. At a high rate of 5C (4450&nbsp;mA/g), NCO-ES electrodes delivered a stabilized specific capacity of 225&nbsp;mAh/g with almost 100{%} Coulombic efficiency over 1000 cycles. Its rate capability and cycle life were found to be superior to NCO-DA electrodes. The nanoscale grain boundaries in the NCO-ES sample enhanced the lithium-ion diffusion and enabled high rate capability. The impedance analysis at different stages of lithiation/delithiation indicates a lower impedance and better kinetics as one of the reasons for better performance of the NCO-ES sample.

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2018

B. Gangaja, Jayasree, S. S., Shantikumar V Nair, and Santhanagopalan, D., “Effect of Lithiation Voltage Limit on the Electrochemical Performance of High Surface Area Anatase TiO2 Nanoparticles and Its Application in Full-Cell Li–Ion Battery”, ChemistrySelect, vol. 3, pp. 12258-12262, 2018.[Abstract]


Abstract Titania based anodes have received considerable interest due to its cycling stability and improved safety. Here, we report the electrochemical performance of high surface area anatase TiO2 nanoparticles synthesized via solvothermal technique. Prepared anatase TiO2 nanoparticles were below 15 nm in average particle size exhibiting high surface area of 251 m2/g and titanium existing in 4+ oxidation state. The electrodes studied by limiting the discharge voltage between 1.0 V and 0.01 V showed significant performance differences. Especially, specific capacity, Coulombic efficiency and storage mechanism of TiO2 depends strongly on lithiation voltage cut-off limit that is discussed in detail. It was established that discharging to 1.0 V showed better performance hence, subsequent studies the lithiation (discharge) was limited to 1.0 V. High rate capability of the electrodes were tested test up to 60 C and long cycle stability up to 1000 cycles (at 10 C rate). As an energy storage solution, a&nbsp;2.0 V full-cell Li-ion battery was fabricated with the TiO2 nanoparticles as anode against surface modified LiCoO2 as cathode. The full-cell delivered specific capacities about 165 mAh/g and 105 mAh/g at current densities of 150 mA/g and 3765 mA/g respectively. It also exhibited 126 mAh/g capacity and 85% retention at the end of 100 cycles at a current density of 1000 mA/g. The full-cell delivered a maximum power density of 5.5 kW/kg and a corresponding energy density of 185 Wh/kg.

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2018

S. Kuttappan, Mathew, D., Jo, J. - I., Tanaka, R., Menon, D., Ishimoto, T., Nakano, T., Shantikumar V Nair, Dr. Manitha B. Nair, and Tabata, Y., “Dual Release of growth Factor from Nanocomposite Fibrous Scaffold Promotes Vascularisation and Bone Regeneration in Rat Critical Sized Calvarial Defect.”, Acta Biomaterialia, vol. 78, pp. 36-47, 2018.[Abstract]


A promising strategy for augmenting bone formation involves the local delivery of multiple osteoinductive and vasculogenic growth factors. However, success depends on sustained growth factor release and its appropriate combination to induce stem cells and osteogenic cells at the bony site. Herein, we have developed a nanocomposite fibrous scaffold loaded with fibroblast growth factor 2 (FGF2), vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP2) and its ability to promote vascularisation and bone regeneration in critical sized calvarial defect was compared to the scaffold with VEGF + BMP2 and FGF2 + BMP2. Simple loading of growth factors on the scaffold could provide a differential release pattern, both in vitro and in vivo (VEGF release for 1 week where as BMP2 and FGF2 release for 3 weeks). Among all the groups, dual growth factor loaded scaffold (VEGF + BMP2 &amp; FGF2 + BMP2) enhanced vascularisation and new bone formation, but there was no difference between FGF2 and VEGF loaded scaffolds although its release pattern was different. FGF2 mainly promoted stem cell migration, whereas VEGF augmented new blood vessel formation at the defect site. This study suggests that biomimetic nanocomposite scaffold is a promising growth factor delivery vehicle to improve bone regeneration in critical sized bone defects.

<p><b>STATEMENT OF SIGNIFICANCE: </b>Many studies have shown the effect of growth factors like VEGF-BMP2 or FGF2-BMP2 in enhancing bone formation in critical sized defects, but there are no reports that demonstrate the direct comparison of VEGF-BMP2 and FGF2-BMP2. In this study, we have developed a nanocomposite fibrous scaffold that could differentially release growth factors like VEGF, BMP2 and FGF2 (VEGF release for 1 week where as BMP2 and FGF2 release for 3 weeks), which in turn promoted neovascularisation and new bone formation in critical sized defects. There was no difference in vascularisation and bone formation induced by VEGF + BMP2 or FGF2 + BMP2. The growth factor was loaded in a simple manner, which would ensure ease of use for the end-user, especially for the surgeons treating a patient in an operating room.</p>

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2018

Manju V., Anitha A., Dr. Deepthy Menon, Dr. Subramania Iyer K., Shantikumar V Nair, and Dr. Manitha B. Nair, “Nanofibrous yarn reinforced HA-gelatin composite scaffolds promote bone formation in critical sized alveolar defects in rabbit model”, Biomedical Materials, vol. 13, no. 6, p. 065011, 2018.[Abstract]


Alveolar ridge resorption and crestal bone loss necessitate the use of bone graft substitutes for dental rehabilitation. The aim of this study was to compare the bone regenerative property of nanofibre incorporated two composite matrices (nanofibrous sheet layered matrix (CS-S) and nanofibrous yarn reinforced matrix (CS-Y)) in critical sized mandibular defect in a rabbit model (under load bearing scenario). Histological evaluation revealed continuous bone formation in the defect implanted with fibre reinforced scaffolds than those without fibres as well as commercial nanoHA-collagen graft. Interestingly, the mineralisation and the mineral density were significantly higher with nanoyarn reinforced scaffolds. Moreover, the compressive strength of new bone formed from CS-Y scaffolds was almost similar to that of native rabbit mandible. It can be concluded that the mechanical strength provided by three-dimensionally reinforced nanoyarns in the matrix could promote bone formation in load bearing mandibular region, and these can be proposed as a scaffold of choice for alveolar bone augmentation and dental rehabilitation.

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2018

J. Joseph, Krishnan, A. G., Cherian, A. M., Rajagopalan, B., Jose, R., Varma, P., Maniyal, V., Balakrishnan, S., Shantikumar V Nair, and Dr. Deepthy Menon, “Transforming Nanofibers into Woven Nanotextiles for Vascular Application”, ACS Applied Materials and Interfaces, vol. 10, pp. 19449-19458, 2018.[Abstract]


This study investigates the unique properties, fabrication technique, and vascular applications of woven nanotextiles made from low-strength nanoyarns, which are bundles of thousands of nanofibers. An innovative robotic system was developed to meticulously interweave nanoyarns in longitudinal and transverse directions, resulting in a flexible, but strong woven product. This is the only technique for producing seamless nanotextiles in tubular form from nanofibers. The porosity and the mechanical properties of nanotextiles could be substantially tuned by altering the number of nanoyarns per unit area. Investigations of the physical and biological properties of the woven nanotextile revealed remarkable and fundamental differences from its nonwoven nanofibrous form and conventional textiles. This enhancement in the material property was attributed to the multitude of hierarchically arranged nanofibers in the woven nanotextiles. This patterned woven nanotextile architecture leads to a superhydrophilic behavior in an otherwise hydrophobic material, which in turn contributed to enhanced protein adsorption and consequent cell attachment and spreading. Short-term in vivo testing was performed, which proved that the nanotextile conduit was robust, suturable, kink proof, and nonthrombogenic and could act as an efficient embolizer when deployed into an artery. © 2018 American Chemical Society.

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2018

G. Gopakumar, Menon, H., Ashok, A., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “Two Dimensional Layered Electron Transport Bridges in Mesoscopic TiO2 for Dye Sensitized Solar Cell Applications”, Electrochimica Acta, vol. 267, pp. 63 - 70, 2018.[Abstract]


The present work demonstrates the possibility of facilitating electron transport in mesoscopic titanium dioxide (TiO2) by incorporating nanoflakes of layered molybdenum disulfide (MoS2) as an alternate electron transport bridge. Results suggest that performance of dye sensitized solar cells (DSSCs) can be increased up to ∼16% (from 7.39% to 8.55%) by incorporating 0.2 wt % of MoS2 into the bulk of TiO2, due to the significant improvement in electron lifetime from 8 ms to 23 ms. The nanoflakes of MoS2 form alternate electron transport bridges in the bulk TiO2 nanoparticle film through which photo-injected electrons travel more efficiently to reach transparent electrode compared to DSSCs utilize only TiO2 without MoS2. Presence of atomically thin layered MoS2 nanoflakes in the bulk of TiO2 assist the photo-electrons to skip electron-hole capture processes occur through TiO2 surface states to avoid the interfacial recombination. Further increment in the concentration of MoS2 suppresses the resulting DSSC performance by blocking the porosity which results in less dye adsorption and hence lower photocurrent values

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2018

A. Ashok, Vijayaraghavan, S. N., Unni, G. E., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “On the Physics of Dispersive Electron Transport Characteristics in SnO 2 Nanoparticle-based Dye Sensitized Solar Cells”, Nanotechnology, vol. 29, p. 175401, 2018.[Abstract]


The present study elucidates dispersive electron transport mediated by surface states in tin oxide (SnO 2 ) nanoparticle-based dye sensitized solar cells (DSSCs). Transmission electron microscopic studies on SnO 2 show a distribution of ∼10 nm particles exhibiting (111) crystal planes with inter-planar spacing of 0.28 nm. The dispersive transport, experienced by photo-generated charge carriers in the bulk of SnO 2 , is observed to be imposed by trapping and de-trapping processes via SnO 2 surface states present close to the band edge. The DSSC exhibits 50% difference in performance observed between the forward (4%) and reverse (6%) scans due to the dispersive transport characteristics of the charge carriers in the bulk of the SnO 2 . The photo-generated charge carriers are captured and released by the SnO 2 surface states that are close to the conduction band-edge resulting in a very significant variation; this is confirmed by the hysteresis observed in the forward and reverse scan current–voltage measurements under AM1.5 illumination. The hysteresis behavior assures that the charge carriers are accumulated in the bulk of electron acceptor due to the trapping, and released by de-trapping mediated by surface states observed during the forward and reverse scan measurements

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2018

G. Gopakumar, Ashok, A., Vijayaraghavan, S. N., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “MoO3 Surface Passivation on TiO2: An Efficient Approach to Minimize Loss in Fill Factor and Maximum Power of Dye Sensitized Solar Cell”, Applied Surface Science, vol. 447, pp. 554 - 560, 2018.[Abstract]


The present study demonstrates the possibility for improving the performance of dye sensitized solar cell (DSSC) only by minimizing the loss in fill factor (FF) and maximum power point (PMAX) which can be achieved by passivating the nanocrystalline titanium dioxide (TiO2) using physical vapor deposited molybdenum trioxide (MoO3) thin films. The effect of MoO3 coated TiO2 on charge carrier transport was examined in resulting DSSCs and observed that  ∼14% enhancement in efficiency is possible for 5 min passivation of MoO3 on TiO2. The physical vapor deposited MoO3 films were  ∼75% transparent in the spectral range of 350–800 nm with an optical bandgap of  ∼3.1 eV. The wide bandgap MoO3 films facilitate the incoming photons to reach the sensitizing dye to generate excitons. The 14% enhancement in the performance of DSSC by MoO3 passivation is observed through improving only the FF and PMAX while it does not contribute anything significantly to current density and open circuit voltage. Electrochemical impedance spectroscopic studies further confirmed these observations through photo-electron lifetime, which remains constant both in the bulk of pristine TiO2 and MoO3 passivated TiO2 and it further confirms the effect of MoO3 passivation on FF and PMAX in DSSCs.

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2018

H. Menon, Gopakumar, G., Vijayaraghavan, S. N., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “2D Layered MoS2 Incorporated TiO2 Nanofiber Based Dye Sensitized Solar Cells”, ChemistrySelect , 2018.

2018

Vinod Soman Pillai, Rameshwari R. Kundargi, Fabia Edathadathil, Shantikumar V Nair, Thilak, J., Roshini Anney Mathew, Xavier, T., Padmanabha Shenoy, and Krishnakumar N. Menon, “Identification of Prolargin Expression in Articular Cartilage and its Significance in Rheumatoid Arthritis Pathology”, International Journal of Biological Macromolecules, vol. 110, pp. 558-566, 2018.[Abstract]


Qualitative 2D gel-electrophoresis (2DE) protein profiling for osteoarthritis (OA) and rheumatoid arthritis (RA) is challenging because of selective protein loss due to discrepancies in protein precipitation methodologies. Thus, we aimed at developing qualitative proteinrepresentation from OA/RA articular cartilage without protein precipitation towards identification of clinically relevant proteins. Chondroitinase digested human articular cartilages from RA patients were subjected to protein extraction using guanidinium hydrochloride (GuHCl) or 8 M urea with 10 or 2% ASB-14-4 or 0.45 M urea with 2% ASB-14-4 with cetylpyridinium chloride (CPC). The GuHCl extract is further protein precipitated with acetone or ammonium acetate-methanol or centricon-fractionated using 100 kDa cut filters and protein precipitated using ethanol. Processed extracts were subjected to 2DE to identify protein profiles. Poor proteins representations were observed in 2D gels with protein precipitated samples compared to qualitative protein representations seen in 2D gels of 0.45 M urea and 2%ASB-14-4 extraction procedure reproducibly. The strategy circumventing protein precipitation generated qualitative 2D gels. RA vs OA gel comparison showed elevated prolargin levels in RA with biglycan levels remaining unaltered. Up regulation of prolargin in RA suggests the likelihood of an adaptive mechanism to control the increased osteoclastogenesis in RA and may have therapeutic value in controlling the disease.

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2018

S. Deepthi, M. Sundaram, N., Vijayan, P., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Engineering Poly(Hydroxy Butyrate-co-hydroxy Valerate) Based Vascular Scaffolds to Mimic Native Artery”, International Journal of Biological Macromolecules, vol. 109, pp. 85 - 98, 2018.[Abstract]


Electrospun tri-layered fibrous scaffold incorporating VEGF and Platelet Factor Concentrate (PFC) in multiple layers having different layer architectures was designed to mimic native artery. The scaffold consisted of longitudinally aligned poly(hydroxy butyrate-co-hydroxy valerate) (PHBV) and poly(vinyl alcohol) (PVA) nanofibers (inner layer), radially aligned PHBV-elastin nanofibers (middle layer) to provide the bi-directional alignment and combination of longitudinally aligned PHBV-elastin and random PHBV/PVA multiscale fibers (peripheral layer). Tubular constructs of diameter &lt;6 mm were developed. The developed electrospun fibers were characterised by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy and Tensile tests. Further the burst strength, compliance and stiffness index of tri-layered tubular scaffold was evaluated. SEM images of fibrous layers showed the typical longitudinal and radial alignment of fibers in the tubular construct. SEM images showed that the prepared PHBV nanofibers were in the range of 500–800 nm and PHBV microfibers were of 1–2 μm in diameter in the tri-layered electrospun membrane. PVA nanofibers were of size 200–250 nm. The tensile strength, percentage compliance and stiffness index of tri-layered membrane was in accordance with that of native small blood vessels. The developed tri-layered membrane was blood compatible, with hemolysis degree 0.85 ± 0.21% and did not activate platelets. Controlled release of VEGF and PFC was observed from the scaffold. The biocompatibility of the tri-layered scaffold was evaluated using HUVECs, SMCs and MSCs and SMCs infiltration from the outer layer was also evaluated. Specific protein expression for the HUVECs and SMCs was evaluated by flow cytometry and immunocytochemistry. HUVECs and SMCs exhibited good elongation and alignment along the direction of fibers and was found to maintain its CD31, VE-Cadherin and αSMA expression respectively. The results highlight the importance of bi-directional fiber alignment on the tri-layered electrospun scaffold as a suitable architectural prototype for vascular scaffolds to mimic the native arteries.

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2018

S. Padmakumar, Parayath, N., Leslie, F., Shantikumar V Nair, Dr. Deepthy Menon, and Amiji, M. M., “Intraperitoneal Chemotherapy for Ovarian Cancer using Sustained-Release Implantable Devices”, Expert Opinion on Drug Delivery, vol. 15, no. 5, pp. 481-494, 2018.[Abstract]


INTRODUCTION: Epithelial ovarian cancer (EOC) remains to be the most lethal of all gynecological malignancies mainly due to its asymptomatic nature. The late stages are manifested with predominant metastases confined to the peritoneal cavity. Although there has been a substantial progress in the treatment avenue with different therapeutic interventions, the overall survival rate of patients remain poor due to relapse and drug resistance. Areas covered: The pharmacokinetic advantages offered by intraperitoneal (IP) chemotherapy due to peritoneal-plasma barrier can be potentially exploited for EOC relapse treatment. The ability to retain high concentrations of chemo-drugs with high AUC peritoneum/plasma for prolonged durations in the peritoneal cavity can be utilized effectively through the clinical adoption of drug delivery systems (DDSs) which obviates the need for indwelling catheters. The metronomic dosing strategy could enhance anti-tumor efficacy with a continuous, low dose of chemo-drugs providing minimal systemic toxicity. Expert opinion: The development of a feasible, non-catheter based, IP DDS, retaining the peritoneal-drug levels, with less systemic levels could offer significant survival advantages as a patient-compliant therapeutic strategy. Suturable-implantable devices based on metronomic dosing, eluting drug in a sustained manner at low doses, could be implanted surgically post-debulking for treatment of refractory EOC patients.

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2018

S. Chandrashekaran, Karthikeyan, S., Balakrishnan, A., Nair, S., Kumar, M. Kumaran Sa, Vattathara, J. Jose, Krishnakumar N. Menon, and Shantikumar V Nair, “Expression and Purification of Quinine Dihydro Pteridine Reductase from Astrocytes and its Significance in the Astrocyte Pathology”, International Journal of Biological Macromolecules, vol. 110, pp. 567-572, 2018.[Abstract]


<p>Quinine dihydropteridinereductase (QDPR) is involved in the synthesis of tetradihydrobiopteridine (BH4) that serve as cofactor for many aromatic hydroxylases including induced nitric oxide synthase (NOS) leading to NO production. Increased activity of QDPR has been associated with decrease levels of TGF-β, a cytokine that regulates the immune response and that elevated levels of NO has been associated with neurodegenerative diseases. Thus, expression of QDPR in astrocytes is essential to study the pathological changes observed in many neurodegenerative disorders. We have expressed QDPR in astrocytes and generated stably expressing clones that overexpresses QDPR. We further verified the specificity of QDPR expression using immunofluorescence and immunoblotting. To further confirm, we purified QDPR using Ni-NTA column and subjected the purified fraction to immunoblotting using anti-QDPR antibody and identified two major protein products of QDPR resolving at 25 and 17 kDa as reported in the literature. In order to further assess the significance of QDPR expression, we verified the expression of iNOS in QDPR over expressing cells. We show for the first time statistically significant up regulation of iNOS in QDPR overexpressing astrocytes. Increased expression of iNOS associated with astrocyte pathology seen in many neurodegenerative disorders may have implications in autoimmune neurodegenerative disorders.</p>

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2018

S. Vignesh, Gopalakrishnan, A., Poorna, M. R., Shantikumar V Nair, Dr. Jayakumar Rangasamy, and Dr. Ullas Mony, “Fabrication of Micropatterned Alginate-gelatin and K-carrageenan Hydrogels of Defined Shapes using Simple Wax Mould Method as a Platform for Stem Cell/induced Pluripotent Stem Cells (iPSC) Culture”, International Journal of Biological Macromolecules, vol. 112, pp. 737-744, 2018.[Abstract]


Micropatterning techniques involve soft lithography, which is laborious, expensive and restricted to a narrow spectrum of biomaterials. In this work we report, first time employment of patterned wax moulds for generation of micropatterned alginate-gelatin and κ-carrageenan (κ-CRG) hydrogel systems by a novel, simple and cost effective method. We generated and characterized uniform and reproducible micropatterned hydrogels of varying sizes and shapes such as square projections, square grooves, and circular grids and crisscrossed hillocks. The rheological analysis showed that κ-carrageenan hydrogels had higher gel strength when compared to alginate-gelatin hydrogels. Human Mesenchymal stem cells (hMSCs) and Human Induced Pluripotent Stem Cells (hiPSCs) were found to be cytocompatible with these hydrogels. This micropatterned hydrogel system may have potential application in tissue engineering and also in understanding the basic biology behind the stem cell/iPSC fate.

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2018

B. Gangaja, Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Interface-Engineered LiTiO-TiO Dual-Phase Nanoparticles and CNT Additive for Supercapacitor-Like High-Power Li-ion Battery Applications”, Nanotechnology, vol. 29, no. 9, p. 095402, 2018.[Abstract]


The single-pot synthesis of dual-phase spinel-LiTiO and anatase-TiO (LTO-TiO) nanoparticles over all the phase fractions ranging from pure LTO to pure TiO is conducted. Carrying out the process over the complete range enabled the identification of a unique weight ratio of 85:15 (LTO:TiO), providing the best combination of capacity, rate capability and cycling stability. We show that for this composition dual-phase nanoparticles have a predominant interfacial orientation of (111)∣∣(004) , while it is (111)∣∣(101) for other compositions. This study therefore shows that the dual-phase interface with these specific orientations gives the best performance. The synergistic combination of dual-phase nanoparticles with multi-wall carbon nanotubes improves the performance further. This results in an electrode with supercapacitor-like rate capability delivering high discharge capacities of 174, 127, 119, 110, 101 and 91 mAh g at specific currents of 2000, 6000, 12 000, 18 000, 24 000 and 30 000 mA g, respectively. A discharge capacity of 174 mAh g at a specific current of 2000 mA g with only 0.005% capacity loss per cycle over 3000 cycles is demonstrated. At current densities of 6000, 12 000 and 24 000 mA g, stable cycling is obtained for 1500 cycles. The present work enables nano-engineered interfaces in LTO-TiO dual-phase nanoparticles with an electrochemical performance that is better than its individual components, opening up the potential for high-power Li-ion battery applications.

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2018

Vignesh S, A, S., Annapoorna, M., R, J., Subramania, I., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Injectable Deferoxamine Nanoparticles Loaded Chitosan-hyaluronic Acid Coacervate Hydrogel for Therapeutic Angiogenesis”, Colloids Surf B Biointerfaces, vol. 161, pp. 129-138, 2018.[Abstract]


<p>In this study, an injectable chitosan-hyaluronic acid (CS-HA) based hydrogel was designed incorporating pro-angiogenic molecule, deferoxamine loaded PLGA nanoparticles (DFO NPs), for enhancing angiogenesis. DFO-NPs were prepared by double emulsion solvent diffusion technique and characterized for their physicochemical properties. The DLS and SEM analysis showed an average particle size of 220±71nm with spherical morphology and the encapsulation efficiency was found to be 30±5%. An ECM mimicking chitosan-hyaluronic acid (CS-HA) coacervate hydrogel was prepared. Both free DFO and DFO NPs were entrapped into the prepared CS-HA composite hydrogel. The hydrogels were characterized by SEM, FTIR and Rheology. Addition of DFO NPs did not affect the injectablility and flowability of developed hydrogels. In vitro DFO release from the prepared composite hydrogels showed controlled release over a period of 10days. Both the hydrogel systems showed excellent cyto-compatability and good cell proliferation for rASCs as well as HUVECs. The DFO and DFO NPs loaded composite hydrogels revealed effective tube formation in comparison with control hydrogels without DFO and DFO NPs. The in vivo angiogenic evaluation of the free DFO and DFO NPs (0.025%w/w) loaded composite hydrogels were studied by injecting the developed hydrogel subcutaneously into mice for 2-4 weeks. The DFO NPs loaded composite hydrogel had enhanced neovascularization when compared to control gels. Thus, the developed DFO NPs loaded composite hydrogel could potentially be used for therapeutic angiogenesis.</p>

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2018

F. Basheer, Melge, A. R., Sasidharan, A., Shantikumar V Nair, Dr. Manzoor K., and Dr. Gopi Mohan C., “Computational Simulations and Experimental Validation of Structure- Physicochemical Properties of Pristine and Functionalized Graphene: Implications for Adverse Effects on p53 Mediated DNA Damage Response”, International Journal of Biological Macromolecules, vol. 110, pp. 540-549, 2018.[Abstract]


<p>Recent reports indicated DNA damaging potential of few-layer graphene in human cell systems. Here, we used computational technique to understand the interaction of both pristine (pG) or carboxyl functionalized graphene (fG) of different sizes (1, 6, and 10nm) with an important DNA repair protein p53. The molecular docking study revealed strong interaction between pG and DNA binding domains (DBD) of p53 with binding free energies (BE) varying from -12.0 (1nm) to -34 (6nm)kcal/mol, while fG showed relatively less interaction with BE varying from -6.7 (1nm) to -11.1 (6nm)kcal/mol. Most importantly, pG or fG bound p53-DBDs could not bind to DNA. Further, microarray analysis of human primary endothelial cells revealed graphene intervention on DNA damage and its structure-properties effect using comet assay studies. Thus, computational and experimental results revealed the structure-physicochemical property dependent adverse effects of graphene in DNA repair protein p53.</p>

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2017

A. Anitha, Menon, D., Sivanarayanan, T. B., Dr. Manzoor K., Mohan, C. C., Shantikumar V Nair, and Nair, M. B., “Bioinspired Composite Matrix Containing Hydroxyapatite-Silica Core-Shell Nanorods for Bone Tissue Engineering”, ACS Applied Materials and Interfaces, vol. 9, no. 32, pp. 26707-26718, 2017.

2017

S. B.N., S.R., S., A.G, M., and Shantikumar V Nair, “Designing Scaffolds for Bone Tissue Engineering”, Translating Biomaterials for Bone Graft: Bench-Top to Clinical Applications, 2017.[Abstract]


Tissue engineering has been described as “an interdisciplinary field that applies the principles of engineering and life science towards the development of biological substitutes that restore, maintain, or improve tissue or organ function.”1 The history of this emerging field began in the early 1970s and gained popularity in the 1980s through the experimental initiatives of Langer and Vacanti.2 In 1993, Langer and Vacanti described the utilization of a branching network of synthetic biocompatible/biodegradable polymers configured as scaffolds seeded with viable cells, a seminal paper that became the foundation for current advances in the field of tissue engineering.1

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2017

D. T.D., S., M., Shantikumar V Nair, and A.K., R., “Surfactant-assisted Synthesis of Porous TiO2 Nanofibers as an Anode Material for Secondary Lithium ion Batteries”, Sustainable Energy and Fuels, vol. 1, pp. 138-144, 2017.[Abstract]


An optimized amount of cetyltrimethylammonium bromide (CTAB) as a surfactant was used for the first time to fabricate porous TiO2 nanofibers by an electrospinning technique combined with post-annealing at 500 °C for 5 h in air medium. The fabricated porous TiO2 nanofibers were systematically characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, surface area measurements and electrochemical testing. The porous TiO2 nanofibers contained numerous surface pores with an average diameter of ∼80–90 nm. As an anode, the porous TiO2 nanofiber electrode delivered not only a high reversible capacity and excellent cycle stability over 100 cycles but also excellent rate capability at various current rates in comparison to control TiO2 nanofibers (prepared in the absence of CTAB). The rapid transportation of lithium ions and reduced lithium ion diffusion length probably are responsible for the improved electrochemical performances of the porous TiO2 nanofiber electrode synthesized in the presence of the CTAB surfactant.

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2017

S. Reddy Kasireddy, Gangaja, B., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Mn4+ Rich Surface Enabled Elevated Temperature and Full-cell Cycling Performance of LiMn2O4 Cathode Material”, Electrochimica Acta, vol. 250, pp. 359 - 367, 2017.[Abstract]


LiMn2O4 (LMO) cathode exhibiting improved electrochemical performance is reported. X-ray diffraction confirms spinel cubic structure in the bulk with localized structural integrity confirmed by high-resolution Transmission Electron Microscopy (TEM) analysis showing lattice fringes with spacing of 0.48nm corresponding to (111) of spinel LMO. X-ray photoelectron spectroscopy (XPS) study quantified the Mn4+/Mn3+∼2 instead of 1 on the surface of pristine LMO nanoparticles. Mn4+ rich surface improved elevated temperature cycling stability inhibiting Mn-dissolution. The surface rich Mn4+ and almost equal concentration of Mn4+ and Mn3+ in the sub-surface/bulk was confirmed by XPS analysis upon ion-etching. At room temperature, high discharge capacity of ∼110 mAh/g at 2C rate and ∼102 mAh/g at 10C rate is reported for long cycles (over 500). Cycling at 55°C, capacity retention of 81.2% and 72% at the end of 200 cycles for 1C and 10C discharge rates respectively are testified for the electrochemical stability. This is superior elevated temperature performance of LMO electrodes especially, without any surface coating or doping. To demonstrate LMO cathode’s potential, a full-cell against Li4Ti5O12 and commercial graphite anodes were tested that exhibit discharge capacity of 95 mAh/g and 82 mAh/g respectively with retention of ∼82% over 100 cycles. Finally, electrodes after first charge and discharge have been investigated by ex situ XPS to correlate the oxidation states of manganese with pristine LMO.

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2017

A. Ashok, Vijayaraghavan, S. N., Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “Molybdenum Trioxide Thin Film Recombination Barrier Layers for Dye Sensitized Solar Cells”, RSC Advances , vol. 7, pp. 48853-48860, 2017.[Abstract]


A physical vapor deposition based molybdenum trioxide (MoO3) thin film is demonstrated as an efficient reverse-electron recombination barrier layer (RBL) at the fluorine doped tin oxide (FTO)/titanium dioxide (TiO2) interface in dye sensitized solar cells (DSSCs). Thin films of MoO3 show an average optical transmittance of ∼77% in a spectral range of 350–800 nm with bandgap value of ∼3.1 eV. For an optimum thickness of MoO3, deposited for 5 minutes, the resulting DSSCs showed 15% enhancement in efficiency (η) compared to the reference DSSC which did not use MoO3 RBL; this suggests that MoO3 is effectively suppressing interfacial recombination at the FTO/TiO2 interface. Further, increasing the thickness of MoO3 RBL at the FTO/TiO2 interface (20 minutes deposition) is observed to impede charge transport, as noticed with 55% reduction in η compared to the reference DSSC. Thin film MoO3 RBL with an optimum thickness value at the FTO/TiO2 interface efficiently blocks the leaky transport pathways in the mesoporous TiO2 nanoparticle layer and facilitates efficient charge transport as confirmed by electrochemical impedance spectroscopy.

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2017

A. Sivashanmugam, Charoenlarp, P., Deepthi, S., Rajendran, A., Shantikumar V Nair, Iseki, S., and Jayakumar, R., “Injectable Shear-Thinning CaSO/FGF-18-Incorporated Chitin-PLGA Hydrogel Enhances Bone Regeneration in Mice Cranial Bone Defect Model.”, ACS Appl Mater Interfaces, vol. 9, no. 49, pp. 42639-42652, 2017.[Abstract]


<p>For craniofacial bone regeneration, shear-thinning injectable hydrogels are favored over conventional scaffolds because of their improved defect margin adaptability, easier handling, and ability to be injected manually into deeper tissues. The most accepted method, after autografting, is the use of recombinant human bone morphogenetic protein-2 (BMP-2); however, complications such as interindividual variations, edema, and poor cost-efficiency in supraphysiological doses have been reported. The endogenous synthesis of BMP-2 is desirable, and a molecule which induces this is fibroblast growth factor-18 (FGF-18) because it can upregulate the BMP-2 expression  by supressing noggin. We developed a chitin-poly(lactide-co-glycolide) (PLGA) composite hydrogel by regeneration chemistry and then incorporated CaSO and FGF-18 for this purpose. Rheologically, a 7-fold increase in the elastic modulus was observed in the CaSO-incorporated chitin-PLGA hydrogels as compared to the chitin-PLGA hydrogel. Shear-thinning Herschel-Bulkley fluid nature was observed for both hydrogels. Chitin-PLGA/CaSO gel showed sustained release of FGF-18. In vitro osteogenic differentiation showed an enhanced alkaline phosphatase (ALP) expression in the FGF-18-containing chitin-PLGA/CaSO gel when compared to cells alone. Further, it was confirmed by studying the expression of osteogenic genes [RUNX2, ALP, BMP-2, osteocalcin (OCN), and osteopontin (OPN)], immunofluorescence staining of BMP-2, OCN, and OPN, and alizarin red S staining. Incorporation of FGF-18 in the hydrogel increased the endothelial cell migration. Further, the regeneration potential of the prepared hydrogels was tested in vivo, and longitudinal live animal μ-CT was performed. FGF-18-loaded chitin-PLGA/CaSO showed early and almost complete bone healing in comparison with chitin-PLGA/CaSO, chitin-PLGA/FGF-18, chitin-PLGA, and sham control systems, as confirmed by hematoxylin and eosin and osteoid tetrachrome stainings. This shows that the CaSO and FGF-18-incorporated hydrogel is a potential candidate for craniofacial bone defect regeneration.</p>

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2017

A. Ashokan, Somasundaram, V. Harish, Gowd, G. Siddaraman, Anna, I. M., Malarvizhi, G. L., Sridharan, B., Jobanputra, R. B., Peethambaran, R., Unni, A. K. K., Shantikumar V Nair, and Dr. Manzoor K., “Biomineral Nano-Theranostic Agent for Magnetic Resonance Image Guided, Augmented Radiofrequency Ablation of Liver Tumor.”, Scientific Reports, vol. 7, no. 1, p. 14481, 2017.[Abstract]


<p>Theranostic nanoparticles based on biocompatible mineral compositions can significantly improve the translational potential of image guided cancer nano-therapy. Here, we report development of a single-phase calcium phosphate biomineral nanoparticle (nCP) with dual-mode magnetic resonance contrast (T1-T2) together with radiofrequency (RF) mediated thermal response suitable for image-guided RF ablation of cancer. The nanoparticles (NP) are engineered to provide dual MR contrast by an optimized doping concentration (4.1 at%) of paramagnetic ion, Fe, which also renders lossy dielectric character for nCP leading to thermal response under RF exposure. In vivo compatibility and dual-mode MR contrast are demonstrated in healthy rat models. MRI and T2 mapping suggest hepatobiliary clearance by ~96 hours. MRI guided intratumoral injection in subcutaneous rat glioma and orthotopic liver tumor models provide clear visualization of NP in MRI which also helps in quantifying NP distribution within tumor. Furthermore, by utilising RF mediated thermal response, NP treated tumor could be ablated using clinically approved RF ablation system (10 W,13.3 GHz). Real-time in vivo thermal imaging exhibits 119 ± 10% increase in temperature change (ΔT) for NP treated orthotopic liver tumor (ΔT = 51.5 ± 2 °C), compared to untreated healthy liver control (ΔT = 21.5 ± 2 °C). In effect, we demonstrate a promising nano-biomineral theranostic agent for dual-mode MRI combined with radiofrequency ablation of solid tumors.</p>

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2017

A. Raju, Shantikumar V Nair, and Lakshmanan, V. - K., “Biophytum Sensitivum Nanomedicine Reduces Cell Viability and Nitrite Production in Prostate Cancer Cells”, IET Nanobiotechnology, vol. 11, pp. 782-789, 2017.[Abstract]


Phytomedicine research received tremendous attention for novel therapeutic agent due to their safety and low cost. We assessed a novel nanoformulation of Biophytum sensitivum (BS), natural flavonoids for their improved efficacy and superior bioavailability against crude extract for prostate cancer cells (PC3). We prepared a nanomedicine of BS by nanoprecipitation method and size analysis via DLS and SEM revealed a range of 100-118 nm and surface zeta potential as -9.77 mV. FTIR was performed to evaluate functional for presence of carbonyl and aromatic rings, respectively. Human PC3 cells showed concentration at 0.5, 0.8, and 1 mg/ml dependent cytotoxicity 22, 39, and 56% for 24 h, whereas 43, 41, and 67% for 48 h of BS nanomedicine compared with crude 11, 22, and 53% for 24 h and 38, 31, and 60% for 48 h, respectively. Haemocompatibility of BS nanomedicine at the concentration of 0.5, 0.8, and 1 mg/ml did not show blood aggregation. Cellular uptake was confirmed using rhodamine-conjugated BS nanomedicine for 48 h. Interestingly, BS nanomedicine 1 mg/ml decreases the nitrite productions in PC3 cells. Collectively, BS nanomedicine has the potential anti-cancer agents with biocompatible and enhanced efficacy can be beneficial for the treatment of prostate cancer. © The Institution of Engineering and Technology 2017.

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2017

M. Saravanan, Shantikumar V Nair, and Rai, A. K., “Low Temperature Synthesis of Carbon-wrapped CuO Synthesized Without using a Conventional Carbon Source for Li ion Battery Application”, Physica E: Low-Dimensional Systems and Nanostructures, vol. 94, pp. 113-117, 2017.[Abstract]


Carbon-wrapped CuO is synthesized by a facile pyro-synthesis method without using a conventional carbon source to overcome the capacity fading issue of CuO nanoparticles. The microstructure analysis shows that the sample is fully wrapped by a carbon layer. The resultant carbon-wrapped CuO nanocomposite as an anode exhibits high reversible capacity with excellent cycling stability (437.1&nbsp;mAh/g at 0.25&nbsp;C and 365.2&nbsp;mAh/g at 1.0&nbsp;C after 100 cycles) and good rate capability. It is believed that the synergistic effect of CuO and carbon is responsible for the enhanced electrochemical performance of the nanocomposite electrode.

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2017

S. Fazal, Dr. Bindhu Paul, Shantikumar V Nair, and Dr. Deepthy Menon, “Theranostic Iron Oxide/Gold Ion Nanoprobes for MR Imaging and Noninvasive RF Hyperthermia.”, ACS Applied Materials and Interfaces, vol. 9, no. 34, pp. 28260-28272, 2017.[Abstract]


<p>This work focuses on the development of a nanoparticulate system that can be used for magnetic resonance (MR) imaging and E-field noninvasive radiofrequency (RF) hyperthermia. For this purpose, an amine-functional gold ion complex (GIC), [Au(III)(diethylenetriamine)Cl]Cl, which generates heat upon RF exposure, was conjugated to carboxyl-functional poly(acrylic acid)-capped iron-oxide nanoparticles (IO-PAA NPs) to form IO-GIC NPs of size ∼100 nm. The multimodal superparamagnetic IO-GIC NPs produced T2-contrast on MR imaging and unlike IO-PAA NPs generated heat on RF exposure. The RF heating response of IO-GIC NPs was found to be dependent on the RF power, exposure period, and particle concentration. IO-GIC NPs at a concentration of 2.5 mg/mL showed a high heating response (δT) of ∼40 °C when exposed to 100 W RF power for 1 min. In vitro cytotoxicity measurements on NIH-3T3 fibroblast cells and 4T1 cancer cells showed that IO-GIC NPs are cytocompatible at high NP concentrations for up to 72 h. Upon in vitro RF exposure (100 W, 1 min), a high thermal response leads to cell death of 4T1 cancer cells incubated with IO-GIC NPs (1 mg/mL). Hematoxylin and eosin imaging of rat liver tissues injected with 100 μL of 2.5 mg/mL IO-GIC NPs and exposed to low RF power of 20 W for 10 min showed significant loss of tissue morphology at the site of injection, as against RF-exposed or nanoparticle-injected controls. In vivo MR imaging and noninvasive RF exposure of 4T1-tumor-bearing mice after IO-GIC NP administration showed T2 contrast enhancement and a localized generation of high temperatures in tumors, leading to tumor tissue damage. Furthermore, the administration of IO-GIC NPs followed by RF exposure showed no adverse acute toxicity effects in vivo. Thus, IO-GIC NPs show good promise as a theranostic agent for magnetic resonance imaging and noninvasive RF hyperthermia for cancer.</p>

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2017

D. S. Baji, Shantikumar V Nair, and Alok Kumar Rai, “Highly porous disk-like shape of Co3O4 as an anode material for lithium ion batteries”, Journal of Solid State Electrochemistry, pp. 1-7, 2017.[Abstract]


A novel disk-like shape of Co3O4 with high porosity was synthesized by a facile hydrothermal approach followed by calcination at 485 °C for 2 h. In order to further confirm the crystal structure, morphology, particle size, surface area, and porosity of the sample, a series of corresponding characterization techniques were used. The disk-like shape of Co3O4 as an anode delivered excellent rate capability such as 510.5 mAh g−1 at 4.0 C, which is much higher than the theoretical capacity of commercial graphite anode (372 mAh g−1). However, the electrode could not recover the high capacity during the long-term cycling at various higher current rates due to the deformation of the structure as confirmed by the ex situ studies. It is believed that the obtained remarkable structural feature with numerous void pores within the structure may be helpful for short-term cycling due to the large contact areas between the electrode and the electrolyte and a shorter diffusion length for lithium ion insertion but unable to act as a buffer to relax the volume expansion/contraction and alleviate the structural damage of the electrode during long-term cycling. © 2017 Springer-Verlag Berlin Heidelberg

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2017

J. P.V, Shantikumar V Nair, and Dr. Kaladhar Kamalasanan, “Current trend in drug delivery considerations for subcutaneous insulin depots to treat diabetes”, Colloids and Surfaces B: Biointerfaces, vol. 153, pp. 123-131, 2017.[Abstract]


Diabetes mellitus (DM) is a metabolic disorder due to irregularities in glucose metabolism, as a result of insulin disregulation. Chronic DM (Type 1) is treated by daily insulin injections by subcutaneous route. Daily injections cause serious patient non-compliance and medication non-adherence. Insulin Depots (ID) are parenteral formulations designed to release the insulin over a specified period of time, to control the plasma blood glucose level for intended duration. Physiologically, pancreas produces and secretes insulin in basal and pulsatile mode into the blood. Delivery systems mimicking basal release profiles are known as open-loop systems and current marketed products are open-loop systems. Future trend in open-loop systems is to reduce the number of injections per week by enhancing duration of action, by modifying the depot properties. The next generation technologies are closed-loop systems that mimic the pulsatile mode of delivery by pancreas. In closed-loop systems insulin will be released in response to plasma glucose. This review focuses on future trend in open-loop systems; by understanding (a) the secretion of insulin from pancreas, (b) the insulin regulation normal and in DM, (c) insulin depots and (d) the recent progress in open-loop depot technology particularly with respect to nanosystems. © 2017 Elsevier B.V.

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2017

C. C. Mohan, Cherian, A. Mary, Kurup, S., Joseph, J., Nair, M. B., Vijayakumar, M., Shantikumar V Nair, and Dr. Deepthy Menon, “Stable Titania Nanostructures on Stainless Steel Coronary Stent Surface for Enhanced Corrosion Resistance and Endothelialization”, Adv Healthc Mater, vol. 6, no. 11, 2017.[Abstract]


<p>Stainless steel (SS) coronary stents continue to present risk of in-stent restenosis that impact its long term safety and efficacy. The present work focuses on developing a drug-free and polymer-less surface on coronary stents by utilizing a titania (TiO ) nanotexturing approach through hydrothermal processing, that will offer improved stent performance in vivo. Mechanically stable and durable nanotextured coatings are obtained on SS stents that also offer good corrosion resistance. In vitro vascular cell (endothelial and smooth muscle cells) studies on surface modified SS show preferential rapid endothelialization with enhanced nitric oxide production and reduce smooth muscle cell proliferation, in comparison to unmodified SS. In vivo evaluation of the nanotextured stents after subcutaneous implantation in rabbits show reduced irritability and minimal localized inflammatory response. These beneficial effects suggest that the stable, easily scalable titania nanosurface modification strategy on coronary stent surfaces can be a much cheaper alternative to drug eluting stents in addressing in-stent restenosis.</p>

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2017

R. Ramachandran, Junnuthula, V. Reddy, G Gowd, S., Ashokan, A., Thomas, J., Peethambaran, R., Thomas, A., Unni, A. Kodakara K., Panikar, D., Shantikumar V Nair, and Dr. Manzoor K., “Theranostic 3-Dimensional Nano Brain-Implant for Prolonged and Localized Treatment of Recurrent Glioma”, Scientific Reports, vol. 7, p. 43271, 2017.[Abstract]


Localized and controlled delivery of chemotherapeutics directly in brain-tumor for prolonged periods may radically improve the prognosis of recurrent glioblastoma. Here, we report a unique method of nanofiber by fiber controlled delivery of anti-cancer drug, Temozolomide, in orthotopic brain-tumor for one month using flexible polymeric nano-implant. A library of drug loaded (20 wt%) electrospun nanofiber of PLGA-PLA-PCL blends with distinct in vivo brain-release kinetics (hours to months) were numerically selected and a single nano-implant was formed by co-electrospinning of nano-fiber such that different set of fibres releases the drug for a specific periods from days to months by fiber-by-fiber switching. Orthotopic rat glioma implanted wafers showed constant drug release (116.6 μg/day) with negligible leakage into the peripheral blood (<100 ng) rendering ~1000 fold differential drug dosage in tumor versus peripheral blood. Most importantly, implant with one month release profile resulted in long-term (>4 month) survival of 85.7% animals whereas 07 day releasing implant showed tumor recurrence in 54.6% animals, rendering a median survival of only 74 days. In effect, we show that highly controlled drug delivery is possible for prolonged periods in orthotopic brain-tumor using combinatorial nanofibre libraries of bulk-eroding polymers, thereby controlling glioma recurrence.

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2017

J. John, Gangaja, B., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Conformal coating of TiO2 shell on silicon nanoparticles for improved electrochemical performance in Li-ion battery applications”, Electrochimica Acta, vol. 235, pp. 191 - 199, 2017.[Abstract]


Abstract A scalable wet chemical process for conformal TiO2 coating on silicon nanoparticles is investigated for Li-ion battery applications. The stable core-shell composite nanoparticles along with polyacrylic acid (PAA) binder was studied as an anode in Li-ion batteries and compared with bare-Si as a control. By limiting the charge capacity to 1500 mAh g−1, we established stable cycling (zero fade) for over 50 cycles for the core-shell compared to inferior stability (only 30% capacity retention) of the bare-Si nanoparticles at 0.1C rate. Stable capacity of 800 mAh g−1 at 1C rate over 100 cycles was also demonstrated for the core-shell nanoparticle electrode. Transmission electron microscopy and X-ray photoelectron spectroscopy characterizations indicate that in absence of TiO2 the solid electrolyte interface (SEI) layer which forms around Si was about 8–10 nm and composed of Li2O and LiF. In contrast, the \{SEI\} layer around the TiO2 shell has been thinner (about 2–3 nm) and composed of LiF and LixPFyOz, that stabilized the surface leading to improved cycling stability. Thinner \{SEI\} layer and its composition led to lower charge transfer resistance while the interface between the composite and the Cu-current collector has better adhesion compared to the bare-Si electrode. Impedance spectroscopy measurements confirmed the above. More »»

2017

S. P. Madhusudanan, Gangaja, B., Shyla, A. G., A. Nair, S., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Sustainable chemical synthesis for phosphorus-doping of TiO2 nanoparticles by upcycling human urine and impact of doping on energy applications”, ACS Sustainable Chem. Eng, pp. 2393–2399, 2017.[Abstract]


Recently, there has been significant research interest toward sustainable chemical synthesis and processing of nanomaterials. Human urine, a pollutant, requires energy intensive processing steps prior to releasing into rivers and oceans. Upcyling urine has been proposed and practiced as a sustainable process in the past. Doping is one of the foremost processes to elevate the functionality of nanomaterials depending on the applications it is sought for. Phosphorus doping in to TiO2 nanomaterials has been of research interest over a decade now, that has been chiefly done using acidic precursors. Here we demonstrate, upcycling urine, a sustainable process for phosphorus doping into TiO2 lattice. Upon doping the changes in morphology, surface chemistry and band gap is studied in detail and compared with undoped TiO2 that is prepared using deionized water instead of urine. X-ray photoelectron spectroscopy confirmed that the P was replacing Ti in the lattice and exists in P5+ state with a quantified concentration of 2.5–3 at %. P-doped nanoparticles were almost 50% smaller in size with a lower concentration of surface −OH groups and a band gap increase of 0.3 eV. Finally, impact of these changes on energy devices such as dye-sensitized solar cells and li-ion batteries has been investigated. It is confirmed that P-doping induced surface chemical and band gap changes in TiO2 affected the solar cell characteristics negatively, while the smaller particle size and possibly wider surface channels improved Li-ion battery performance. More »»

2017

B. Gangaja, Chandrasekharan, S., Vadukumpully, S., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Surface chemical analysis of CuO nanofiber composite electrodes at different stages of lithiation/delithiation”, Journal of Power Sources, vol. 340, pp. 356 - 364, 2017.[Abstract]


Abstract High aspect ratio, electrospun CuO nanofibers have been fabricated and tested for its electrochemical performance as lithium ion battery anode. These nanofibers are composed of CuO nanoparticles about 35–40 nm in size forming good inter-connected network. Fabricated half cells maintained specific capacity of 310 mAh g−1 at 1C rate for 100 cycles and stabilized capacity of about 120 mAh g−1 at 5C rate for 1000 cycles. Ex situ x-ray photoelectron spectroscopy (XPS) was performed to understand the electrodes surface chemical changes at the end of first discharge, first charge and after tenth charge. The solid electrolyte interface (SEI) layer comprised of LiF, Li2CO3 and Li2O while their quantity varied depending on the stage of lithiation/delithiation. Initially, no copper signal is observed on the surface of the \{SEI\} layer. However, in situ sputtering of the electrodes in the \{XPS\} chamber revealed that at the end of first discharge, formation Cu0 with detectable fraction of LixCuO2 and hydroxide in the \{SEI\} layer. At the end of first charge, a large fraction of Cu2O phase with a small fraction of hydroxide is observed. At the end of 10th charge no change in \{SEI\} layer content but increase in thickness was observed. More »»

2017

A. K. Haridas, Gangaja, B., Srikrishnarka, P., Unni, G. E., A. Nair, S., Shantikumar V Nair, and Dr. Dhamodaran Santhanagopalan, “Spray pyrolysis-deposited nanoengineered TiO2 thick films for ultra-high areal and volumetric capacity lithium ion battery applications”, Journal of Power Sources, vol. 345, pp. 50 - 58, 2017.[Abstract]


Abstract Energy storage technologies are sensitively dependent on electrode film quality, thickness and process scalability. In Li-ion batteries, using additive-free titania (TiO2) as electrodes, we sought to show the potential of spray pyrolysis-deposited nanoengineered films with thicknesses up to 135 μm exhibiting ultra-high areal capacities. Detailed electron microscopic characterization indicated that the achieved thick films are composed of highly crystalline anatase TiO2 particles with sizes on the order of 10–12 nm and porous as well. A 135 μm thick film yielded ultra-high areal and volumetric capacities of 3.7 mAh cm−2 and 274 mAh cm−3, respectively, at 1C rate. Also the present work recorded high Coulombic efficiency and good cycling stability. The best previously achieved capacities for additive-free TiO2 films have been less than 0.25 mAh cm−2 and With additives, best reported areal capacity in the literature has been 2.5 mAh cm−2 at 1C rate, but only with electrode thickness as high as 1400 μm. Formation of through-the-thickness percolation of Ti3+ conductive network upon lithiation contributed substantially for the superior performance. Spray pyrolysis deposition of nanoparticulate TiO2 electrodes have the potential to yield volumetric capacities an order of magnitude higher than the other processes previously reported without sacrificing performance and process scalability. More »»

2017

G. J. Pillai, Dr. Bindhu Paul, Shantikumar V Nair, and Dr. Deepthy Menon, “Influence of Surface Passivation of 2-Methoxyestradiol Loaded PLGA Nanoparticles on Cellular Interactions, Pharmacokinetics and Tumour Accumulation”, Colloids Surf B Biointerfaces, vol. 150, pp. 242-249, 2017.[Abstract]


<p>In the present work, 2-Methoxyestradiol [2ME2] loaded PLGA nanoparticles [NPs] were stabilized with Casein or poly(ethylene glycol) [PEG] and evaluated for its cellular interactions, pharmacokinetics and tumour accumulation. Surface stabilized PLGA nanoparticles prepared through a modified emulsion route possessed similar size, surface charge, drug loading and release characteristics. Particle-cell interactions as well as the anti-angiogenesis activity were similar for both nanoformulations in vitro. However, in vivo pharmacokinetics and tumour accumulation of the drug were substantially improved for the PEGylated nanoformulation. Reduced protein binding was observed for PEG stabilized PLGA NPs. Thus, it was demonstrated that nanoencapsulation of 2-ME2 within PEGylated PLGA nanocarrier could improve its half-life and plasma concentration and thereby increase the tumour accumulation.</p>

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2017

S. Sowmya, Dr. Ullas Mony, Jayachandran, P., Reshma, S., R Kumar, A., Arzate, H., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Tri-Layered Nanocomposite Hydrogel Scaffold for the Concurrent Regeneration of Cementum, Periodontal Ligament, and Alveolar Bone.”, Advanced Healthcare Materials, vol. 6, no. 7, 2017.[Abstract]


A tri-layered scaffolding approach is adopted for the complete and concurrent regeneration of hard tissues-cementum and alveolar bone-and soft tissue-the periodontal ligament (PDL)-at a periodontal defect site. The porous tri-layered nanocomposite hydrogel scaffold is composed of chitin-poly(lactic-co-glycolic acid) (PLGA)/nanobioactive glass ceramic (nBGC)/cementum protein 1 as the cementum layer, chitin-PLGA/fibroblast growth factor 2 as the PDL layer, and chitin-PLGA/nBGC/platelet-rich plasma derived growth factors as the alveolar bone layer. The tri-layered nanocomposite hydrogel scaffold is cytocompatible and favored cementogenic, fibrogenic, and osteogenic differentiation of human dental follicle stem cells. In vivo, tri-layered nanocomposite hydrogel scaffold with/without growth factors is implanted into rabbit maxillary periodontal defects and compared with the controls at 1 and 3 months postoperatively. The tri-layered nanocomposite hydrogel scaffold with growth factors demonstrates complete defect closure and healing with new cancellous-like tissue formation on microcomputed tomography analysis. Histological and immunohistochemical analyses further confirm the formation of new cementum, fibrous PDL, and alveolar bone with well-defined bony trabeculae in comparison to the other three groups. In conclusion, the tri-layered nanocomposite hydrogel scaffold with growth factors can serve as an alternative regenerative approach to achieve simultaneous and complete periodontal regeneration.

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2017

A. Anitha, Joseph, J., Menon, D., Shantikumar V Nair, and Dr. Manitha B. Nair, “Electrospun Yarn Reinforced NanoHA Composite Matrix as a Potential Bone Substitute for Enhanced Regeneration of Segmental Defects.”, Tissue Eng Part A, vol. 23, no. 7-8, pp. 345-358, 2017.[Abstract]


<p>Nanohydroxyapatite (nanoHA) is a well-established synthetic bone substitute with excellent osteoconduction and osteointegration. However, brittleness coupled with slow degradation curtails its load-bearing and bone regeneration potential, respectively. To address these limitations, nanoHA composite matrix reinforced with electrospun fibrous yarns was fabricated and tested in vitro and in vivo. Different weight percentages (5, 10, 15 wt%) and varying lengths (short and continuous) of poly(l-lactic acid) yarns were randomly dispersed in a gelatinous matrix containing nanoHA. This significantly improved the compressive strength as well as work of fracture, especially for continuous yarns at high weight percentages (10 and 15 wt%). Incorporation of yarns did not adversely affect the pore size (50-350 μm) or porosity of the scaffolds as well as the in vitro cellular response. Finally, when tested in a critical-sized femoral segmental defect in rat, the nanocomposite scaffolds induced osteoblast cell infiltration at 2 months that subsequently underwent increased mature lamellar bone formation at 4 months, in both the mid and peripheral defect regions. Histomorphometric analysis demonstrated that new bone formation and biomaterial degradation were significantly enhanced in the composite scaffold when compared to commercially available HA. Overall, the composite matrix reinforced with electrospun yarns proved to be a potential bone substitute having an appropriate balance between mechanical strength, porosity, biodegradation, and bone regeneration ability.</p>

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2016

K. S., K.S., S., K.C., R., Shantikumar V Nair, and K., L. V., “Anti-Proliferative Effect of Tinospora cordifolia Nano Particles in Prostate Cancer Cells”, Journal of Bionanoscience, 2016.

2016

S. K.S., V.-K., L., and Shantikumar V Nair, “Sustained Release of Rottlerin Encapsulated within Poly(D, L-lactic-co-glycolic acid) Nanoparticles Inhibits Migration and Clonogenicity in Pancreatic cancer Cells”, Journal of Nanoscience and Nanotechnology, vol. 16, 2016.[Abstract]


In our present study, we focused on the preparation and evaluation of a stable nano-formulation of small molecule drug rottlerin encapsulated within PLGA (Poly(D, L-lactic-co-glycolic acid)) nanoparticles. The endeavor was to increase therapeutic efficacy of rottlerin against, and drug delivery to, pancreatic cancer cells. Size and morphology analysis by Dynamic light scattering (DLS) and Scanning electron microscopy (SEM) revealed the average size of nanoparticles prepared was 150–300 nm. In vitro drug release study confirmed the suitability of PLGA nanoparticles as a matrix for controlled release of rottlerin. In vitro cytotoxicity assay in MiaPaCa-2 cells showed dose dependent and preferential toxicity on pancreatic cancer cells compared to normal Vero cells. Furthermore, apoptosis mediated cell death was higher in the rottlerin nanoparticles treated cells and there was also a significant delay in cancer cell migration along with reduction in colony formation. Henceforth the study prospects that the potential therapeutic value of rottlerin against pancreatic cancer can have added advantage through its nanoformulation using a suitable polymeric carrier.

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2016

V. H. Somasundaram, Pillai, R., Malarvizhi, G., Anusha Ashokan, Gowd, S., Peethambaran, R., Palaniswamy, S., Unni, A. K. K., Shantikumar V Nair, and Dr. Manzoor K., “Biodegradable Radiofrequency Responsive Nanoparticles for Augmented Thermal Ablation Combined with Triggered Drug Release in Liver Tumors”, ACS Biomaterials Science and Engineering, vol. 2, pp. 768-779, 2016.[Abstract]


Radiofrequency ablation (RFA) and doxorubicin (Dox) chemotherapy are separately approved for liver cancer therapy; however, both have limited success in the clinic due to suboptimal/nonuniform heating and systemic side effects, respectively. Here, we report a biodegradable nanoparticle (NP) system showing excellent RF hyperthermic response together with the ability to locally deliver Dox in the liver under RF trigger and control. The nanosystem was prepared by doping a clinically permissible dose (∼4.3 wt %, 0.03 ppm) of stannous ions in alginate nanoparticles (∼100 nm) coloaded with Dox at ∼13.4 wt % concentration and surface conjugated with galactose for targeting asialo-glycoprotein receptors in liver tumors. Targeted NP-uptake and increased cytotoxicity when combined with RF exposure was demonstrated in HEPG2 liver cancer cells. Following in vitro (chicken liver phantom) demonstration of locally augmented RF thermal response, in vivo scintigraphic imaging of 99Tc-labeled NPs was performed to optimize liver localization in Sprague-Dawley (SD) rats. RF ablation was performed in vivo using a cooled-tip probe, and uniformly enhanced (∼44%) thermal ablation was demonstrated with magnetic resonance imaging along with RF-controlled Dox release. In orthotopic rat liver tumor models, real-time infrared imaging revealed significantly higher (∼20 °C) RF thermal response at the tumor site, resulting in uniform augmented ablation (∼80%) even at a low RF power exposure of 15 W for just 1 min duration. Being a clinically acceptable, biodegradable material, alginate nanoparticles hold strong translational potential for augmented RF hyperthermia combined with triggered drug release.

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2016

A. Mohan, Shantikumar V Nair, and Lakshmanan, V. - K., “Leucas aspera Nanomedicine Shows Superior Toxicity and Cell Migration Retarded in Prostate Cancer Cells”, Applied Biochemistry and Biotechnology, pp. 1-13, 2016.[Abstract]


Prostate cancer is one of the most common malignancies among men worldwide. The main aim of the present work was to clarify the advantages of a nanoformulation of ayurvedic herbal plants. Specifically, we assessed the improved anticancer activity of Leucas aspera nanoparticles compared with methanolic crude extract in PC3 prostate cancer cells and normal cells. L. aspera is a plant that is used in ayurveda due to the antirheumatic, antipyretic, anti-inflammatory, antibacterial, anticancer, and cytotoxic activities. Nanoparticles of L. aspera were prepared from plant methanolic extracts. Cytotoxic effect was studied in the normal and prostate cancer cells. Size and morphology of the formulated nanoparticles was assessed using dynamic light scattering and scanning electron microscopy. In vitro cytotoxicity of L. aspera nanoparticles for PC3 cells was concentration- and time-dependent. In vitro hemolysis assay, cellular uptake studies, cell aggregation studies, and cell migration assay established the anticancerous activity of L. aspera in prostate cancer. More »»

2016

Mab Dangate, Munshi, Ab, Sampath, W. Sb, Boltalina, O. Vc, Strauss, S. Hc, Saravanan, Ca, and Shantikumar V Nair, “Investigation of Organic Small Molecules and Polymer Compounds for CdTe back Contact”, Conference Record of the IEEE Photovoltaic Specialists Conference, vol. 2016-November, pp. 1438-1442, 2016.[Abstract]


Different organic compounds are evaluated to form back contact for CdTe photovoltaics (PV) and to study the effect of band alignment. CdTe devices with CdS n-type window layer were fabricated using closed space sublimation (CSS) and organic back contact layers were deposited using dip coating. In order to prepare photovoltaic devices, the appropriate deposition parameters and thicknesses of organic compounds were selected experimentally. The best results were obtained with dip coated PEDOT-PSS aqueous dispersion with high electrical conductivity. The performance of devices with organic back contacts are compared to those with baseline CdTe devices with reduced copper doping.

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2016

S. Deepthi, Gafoor, A. A. Abdul, Sivashanmugam, A., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Nanostrontium ranelate incorporated injectable hydrogel enhanced matrix production supporting chondrogenesis: In vitro”, Journal of Materials Chemistry B, vol. 4, pp. 4092-4103, 2016.[Abstract]


An injectable hydrogel, with the advantage of adaptability to defect sites, patient compliance, controlled flowability and high water uptake capability, was explored as a prototype for cartilage tissue regeneration. Chitosan and fibrin are natural biomaterials that are biocompatible, biodegradable, resemble the ECM of the tissues and contain cell adhesion sites thereby providing a support for cell growth. In this study strontium ranelate, a drug recently studied to enhance cartilage regeneration, was encapsulated in chitosan nanoparticles to provide sustained delivery of the drug content within the composite gel (chitosan/alginate/fibrin hydrogel). The developed nanocomposite gel was characterized using SEM, EDS and FTIR. The particle size of the strontium ranelate loaded chitosan nanoparticles was found to be 160 ± 30 nm. The encapsulation and loading efficiency values of strontium ranelate were found to be 40 ± 10% and 36 ± 2% respectively. Rheological data showed a storage modulus of 5.514 ± 0.102 kPa with thermal stability over the studied temperature range, and the gel properties could be restored within 10 s after the application of a high shear rate. The cytocompatibility and chondrogenic potential was analyzed using human mesenchymal stem cells (hMSCs) to evaluate the applicability of the developed hydrogel for cartilage regeneration. hMSCs were found to be viable in the developed hydrogels and chondrogenic differentiation of hMSCs was observed which was confirmed with enhanced proteoglycan and collagen synthesis. These results indicated that the developed injectable nanocomposite gel would be a suitable system for cartilage regeneration. © 2016 The Royal Society of Chemistry.

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2016

K. M. Sajesh, Kiran, K., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Sequential layer-by-layer electrospinning of nano SrCO3/PRP loaded PHBV fibrous scaffold for bone tissue engineering”, Composites Part B: Engineering, vol. 99, pp. 445-452, 2016.[Abstract]


Development of scaffolds with a blend of osteoinductive and osteoconductive properties is believed to be an effective approach towards bone regeneration. In our current research, a biodegradable Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) [PHBV]/nano strontium carbonate/Platelet Rich Plasma (PRP) composite scaffold was fabricated using sequential layer-by-layer electrospinning method. The synthesized nSrCO3 nanoparticles were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and further the developed electrospun scaffolds were taken for in vitro assessments. Fiber diameter of the composite fibrous scaffold ranges from 400 to 800 nm. Cell proliferation analysis signifies the role of PRP in the developed scaffold. Osteogenic differentiation of hMSCs was confirmed by measuring the ALP concentration and mineral deposition on the scaffolds and demonstrates considerable enhancement on the composite scaffold. These preliminary results demonstrate that the developed electrospun biocomposite scaffold could serve as a better platform for bone regeneration. More »»

2016

Shantikumar V Nair, Baranwal, G., Chatterjee, M., Sachu, A., Dr. Anil Kumar V., Chinchu Bose, Dr. Asoke Banerji, and Dr. Raja Biswas, “Antimicrobial Activity of Plumbagin, a Naturally Occurring Naphthoquinone from Plumbago Rosea, against Staphylococcus Aureus and Candida Albicans”, International Journal of Medical Microbiology, vol. 306, pp. 237-248, 2016.[Abstract]


Candida albicans and Staphylococcus aureus are opportunistic pathogens. Despite causing a number of independent infections, both pathogens can co-infect to cause urinary tract infections, skin infections, biofilm associated infections, sepsis and pneumonia. Infections of these two pathogens especially their biofilm associated infections are often difficult to treat using currently available anti-bacterial and anti-fungal agents. In order to identify a common anti-microbial agent which could confer a broad range of protection against their infections, we screened several phytochemicals and identified plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), a phytochemical from Plumbago species as a potent antimicrobial agent against S. aureus and C. albicans, with a minimum inhibitory concentration of 5 μg/ml. Antimicrobial activity of plumbagin was validated using an ex-vivo porcine skin model. For better understanding of the antimicrobial activity of plumbagin, a Drosophila melanogaster infection model was used, where D. melanogaster was infected using S. aureus and C. albicans, or with both organisms. The fly's survival rate was dramatically increased when infected flies were treated using plumbagin. Further, plumbagin was effective in preventing and dispersing catheter associated biofilms formed by these pathogens. The overall results of this work provides evidence that plumbagin, possesses an excellent antimicrobial activity which should be explored further for the treatment of S. aureus and C. albicans infections.

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2016

P. Preetham, Mohapatra, S., Shantikumar V Nair, Dr. Dhamodaran Santhanagopalan, and Alok Kumar Rai, “Ultrafast pyro-synthesis of NiFe2O4 nanoparticles within a full carbon network as a high-rate and cycle-stable anode material for lithium ion batteries”, RSC Advances, vol. 6, pp. 38064-38070, 2016.[Abstract]


NiFe2O4 nanoparticles fully anchored within a carbon network were prepared via a facile pyro-synthesis method without using any conventional carbon sources. The surface morphology was investigated using field-emission scanning electron microscopy, which confirmed the full anchoring of NiFe2O4 nanoparticles within a carbon network. The primary particle size of NiFe2O4 is in the range of 50-100 nm. The influence of the carbon network on the electrochemical performance of the NiFe2O4/C nanocomposite was investigated. The electrochemical results showed that the NiFe2O4/C anode delivered a reversible capacity of 381.8 mA h g-1 after 100 cycles at a constant current rate of 1.0C, and when the current rate is increased to a high current rate of 5.0C, a reversible capacity of 263.7 mA h g-1 is retained. The obtained charge capacity at high current rates is better than the reported values for NiFe2O4 nanoparticles. The enhanced electrochemical performance can be mainly ascribed to the high electrical conductivity of the electrode, the short diffusion path for Li+ ion transportation in the active material and synergistic effects between the NiFe2O4 nanoparticles and carbon network, which buffers the volume changes and prevents aggregation of NiFe2O4 nanoparticles during cycling. © The Royal Society of Chemistry 2016.

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2016

S. Mohapatra, Shantikumar V Nair, Dr. Dhamodaran Santhanagopalan, and Alok Kumar Rai, “Nanoplate and mulberry-like porous shape of CuO as anode materials for secondary lithium ion battery”, Electrochimica Acta, vol. 206, pp. 217-225, 2016.[Abstract]


Facile hydrothermal synthesis of nanoplate and mulberry-like porous shape of CuO nanostructures was developed as anode materials for application in lithium ion batteries. The powder X-ray diffraction patterns of both the samples were indexed well to a pure monoclinic phase of CuO with no impurities. The CuO sample synthesized at different pH and reaction temperature exhibited nanoplate with average width and length of ∼150-300 nm and ∼300-700 nm and mulberry-like porous shape of CuO with average length of ∼300-400 nm. Electrochemical tests show that the lithium storage performances of both the nanoplate and mulberry-like samples are influenced more closely to its structural aspects than their morphology and size factors. The CuO nanoplate electrode exhibits high reversible charge capacity of 279.3 mAh g-1 at 1.0C after 70 cycles, and a capacity of 150.2 mAh g-1 even at high current rate of 4.0C during rate test, whereas the mulberry-like porous shape of CuO anode delivers only 131.4 mAh g-1 at 1.0C after 70 cycles and 121.7 mAh g-1 at 4.0C. It is believed that the nanoplate type architecture is very favorable to accommodate the volume expansion/contraction and aggregation of particles during the cyclic process. In contrast, the mulberry-like porous morphology could not preserve the integrity of the structure and completely disintegrated into nanoparticles during Li+ ion insertion/deinsertion due to the loose contact between the particles. © 2016 Elsevier Ltd. All rights reserved.

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2016

A. R. Kumar, Sivashanmugam, A., Deepthi, S., Bumgardner, J. D., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Nano-Fibrin Stabilized CaSO4 Crystals Incorporated Injectable Chitin Composite Hydrogel for Enhanced Angiogenesis & Osteogenesis”, Carbohydrate Polymers, vol. 140, pp. 144-153, 2016.[Abstract]


Calcium sulfate (CaSO4), an excellent biodegradable bone forming agent that is an ideal choice as additive in gels, however, its disadvantage being poor gel rheology and angiogenesis. Here, we have synthesized chitin-CaSO4-nano-fibrin based injectable gel system which shows improved rheology and angiogenic potential. Rheological studies showed that the composite gel was a shear thinning gel with elastic modulus of 15.4 ± 0.275 kPa; a 1.67 fold increase over chitin control. SEM and XRD analyses revealed the effect of nano-fibrin (nFibrin) in transforming CaSO4 crystal shape from needle to hexagonal. It also masked the retarding effect of CaSO4 towards in vitro early cell attachment and angiogenesis using rabbit adipose derived mesenchymal stem cells (rASCs) and HUVECs, respectively. rASCs osteogenesis was confirmed by spectrophotometric endpoint assay, which showed 6-fold early increase in alkaline phosphatase levels and immuno-cytochemistry analysis. These in vitro results highlight the potential of injectable chitin-CaSO4-nFibrin gel for osteo-regeneration via enhanced angiogenesis.

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2016

A. Sasidharan, Swaroop, S., Chandran, P., Shantikumar V Nair, and Dr. Manzoor K., “Cellular and molecular mechanistic insight into the DNA-damaging potential of few-layer graphene in human primary endothelial cells”, Nanomedicine: Nanotechnology, Biology, and Medicine, vol. 12, pp. 1347-1355, 2016.[Abstract]


Despite graphene being proposed for a multitude of biomedical applications, there is a dearth in the fundamental cellular and molecular level understanding of how few-layer graphene (FLG) interacts with human primary cells. Herein, using human primary umbilical vein endothelial cells as model of vascular transport, we investigated the basic mechanism underlying the biological behavior of graphene. Mechanistic toxicity studies using a battery of cell based assays revealed an organized oxidative stress paradigm involving cytosolic reactive oxygen stress, mitochondrial superoxide generation, lipid peroxidation, glutathione oxidation, mitochondrial membrane depolarization, enhanced calcium efflux, all leading to cell death by apoptosis/necrosis. We further investigated the effect of graphene interactions using cDNA microarray analysis and identified potential adverse effects by down regulating key genes involved in DNA damage response and repair mechanisms. Single cell gel electrophoresis assay/Comet assay confirmed the DNA damaging potential of graphene towards human primary cells. © 2016 Elsevier Inc.

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2016

S. Padmakumar, Joseph, J., Neppalli, M. H., Mathew, S. E., Shantikumar V Nair, Dr. Sahadev Shankarappa, and Dr. Deepthy Menon, “Electrospun Polymeric Core-sheath Yarns as Drug Eluting Surgical Sutures”, ACS Applied Materials and Interfaces, vol. 8, pp. 6925-6934, 2016.[Abstract]


Drug-coated sutures are widely used as delivery depots for antibiotics and anti-inflammatory drugs at surgical wound sites. Although drug-laden coating provides good localized drug concentration, variable loading efficiency and release kinetics limits its use. Alternatively, drug incorporation within suture matrices is hampered by the harsh fabrication conditions required for suture-strength enhancement. To circumvent these limitations, we fabricated mechanically robust electrospun core-sheath yarns as sutures, with a central poly-l-lactic acid core, and a drug-eluting poly-lactic-co-glycolic acid sheath. The electrospun sheath was incorporated with aceclofenac or insulin to demonstrate versatility of the suture in loading both chemical and biological class of drugs. Aceclofenac and insulin incorporated sutures exhibited 15% and 4% loading, and release for 10 and 7 days, respectively. Aceclofenac sutures demonstrated reduced epidermal hyperplasia and cellularity in skin-inflammation animal model, while insulin loaded sutures showed enhanced cellular migration in wound healing assay. In conclusion, we demonstrate an innovative strategy of producing mechanically strong, prolonged drug-release sutures loaded with different classes of drugs. © 2016 American Chemical Society.

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2015

Binulal Nelson Sathy, Watson, B. M., Kinard, L. A., Spicer, P. P., Dahlin, R. L., Mikos, A. G., and Shantikumar V Nair, “Bone Tissue Engineering with Multilayered Scaffolds—Part II: Combining Vascularization with Bone Formation in Critical-Sized Bone Defect”, Tissue Engineering Part A, vol. 21, pp. 2495-2503, 2015.[Abstract]


Our previous in vivo study showed that multilayered scaffolds made of an angiogenic layer embedded between an osteogenic layer and an osteoconductive layer, with layer thickness in the 100–400 μm range, resulted in through-the-thickness vascularization of the construct even in the absence of exogenous endothelial cells. The angiogenic layer was a collagen–fibronectin gel, and the osteogenic layer was made from nanofibrous polycaprolactone while the osteoconductive layer was made either from microporous hydroxyapatite or microfibrous polycaprolactone. In this follow-up study, we implanted these acellular and cellular multilayered constructs in critical-sized rat calvarial defects and evaluated their vascularization and bone formation potential. Vascularization and bone formation at the defect were evaluated and quantified using microcomputed tomography (microCT) followed by perfusion of the animals with the radio opaque contrast agent, MICROFIL. The extent of bony bridging and union within the critical-sized defect was evaluated using a previously established scoring system from the microCT data set. Similarly the new bone formation in the defect was quantified from the microCT data set as previously reported. Histological evaluation at 4 and 12 weeks validated the microCT findings. Our experimental results showed that acellular multilayered scaffolds with microscale-thick nanofibers and porous ceramic discs with angiogenic zone at their interface can regenerate functional vasculature and bone similar to that of cellular constructs in critical-sized calvarial defects. This result suggests that suitably bioengineered acellular multilayered constructs can be an improved and more translational approach in functional in vivo bone regeneration.

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2015

M. C.C, A.M., C., A, P., ,, Shantikumar V Nair, K, C., and Dr. Deepthy Menon, “Nanotextured Stainless Steel for Improved Corrosion Resistance and Biological Response in Coronary Stenting”, Nanoscale, vol. 7, no. 2, pp. 832-841, 2015.[Abstract]


Nanosurface engineering of metallic substrates for improved cellular response is a persistent theme in biomaterials research. The need to improve the long term prognosis of commercially available stents has led us to adopt a ‘polymer-free’ approach which is cost effective and industrially scalable. In this study, 316L stainless steel substrates were surface modified by hydrothermal treatment in alkaline pH, with and without the addition of a chromium precursor, to generate a well adherent uniform nanotopography. The modified surfaces showed improved hemocompatibility and augmented endothelialization, while hindering the proliferation of smooth muscle cells. Moreover, they also exhibited superior material properties like corrosion resistance, surface integrity and reduced metal ion leaching. The combination of improved corrosion resistance and selective vascular cell viability provided by nanomodification can be successfully utilized to offer a cell-friendly solution to the inherent limitations pertinent to bare metallic stents.

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2015

M. P. Antony, Moehl, T., Wielopolski, M., Moser, J. - E., Shantikumar V Nair, Yu, Y. - J., Kim, J. - H., Kay, K. - Y., Jung, Y. - S., Yoon, K. Byung, Grätzel, C., Zakeeruddin, S. M., and Gratzel, M., “Long-Range π-Conjugation in Phenothiazine-containing Donor–Acceptor Dyes for Application in Dye-Sensitized Solar Cells”, ChemSusChem, vol. 8, pp. 3859-3868, 2015.[Abstract]


<p>Abstract Four organic donor–π-bridge–acceptor dyes containing phenothiazine as a spacer and cyanoacrylic acid as an acceptor were synthesized and tested as sensitizers in dye-sensitized solar cells (DSCs). The influence of iodide- and cobalt-based redox electrolytes on the photovoltaic device performance was investigated. In these new dyes, systematic π-conjugation was extended by inserting one or two phenothiazine moieties and investigated within the context of the resulting photoinduced charge-transfer properties. A detailed investigation, including transient absorption spectroscopy and quantum chemical methods, provided important information on the role of extended π-conjugation on the photophysical properties and photovoltaic device performance. Overall, the results showed that the extension of π-conjugation by one phenothiazine unit resulted in the best device performance owing to reduced recombination rates, whereas extension by two phenothiazine units reduced dye adsorption on TiO2 probably owing to the increase in molecular size. The performance of the dyes in DSCs was found to be a complex interaction between dye structure and size.</p>

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2015

N. H.A., K.S., S., R.C., K., Shantikumar V Nair, and K., L. V., “Plumbagin Nanoparticles Induce Dose and pH Dependent Toxicity on Prostate Cancer Cells”, Current Drug Delivery, 2015.[Abstract]


Stable nano-formulation of Plumbagin nanoparticles from Plumbago zeylanica root extract was explored as a potential natural drug against prostate cancer. Size and morphology analysis by DLS, SEM and AFM revealed the average size of nanoparticles prepared was 100±50nm. In vitro cytotoxicity showed concentration and time dependent toxicity on prostate cancer cells. However, plumbagin crude extract found to be highly toxic to normal cells when compared to plumbagin nanoformulation, thus confirming nano plumbagin cytocompatibility with normal cells and dose dependent toxicity to prostate cells. In vitro hemolysis assay confirmed the blood biocompatibility of the plumbagin nanoparticles. In wound healing assay, plumbagin nanoparticles provided clues that it might play an important role in the anti-migration of prostate cancer cells. DNA fragmentation revealed that partial apoptosis induction by plumbagin nanoparticles could be expected as a potent anti-cancer effect towards prostate cancer.

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2015

P. Chandran, Pavithran, K., Sidharthan, N., Sasidharan, A., Shantikumar V Nair, and Dr. Manzoor K., “Protein Nanomedicine Exerts Cytotoxicity toward CD34+ CD38– CD123+ Leukemic Stem Cells”, ACS Biomaterials Science & Engineering, vol. 1, pp. 1194-1199, 2015.[Abstract]


The efficacy of protein-vorinostat nanomedicine (NV) is demonstrated in leukemic stem cells (LSC) isolated from refractory acute myeloid leukemia (AML) patient samples, where it successfully ablated both CD34+ CD38– CD123+ LSC and non-LSC “leukemic blast” compartments, without inducing myelosuppression or hemotoxicity. Besides, NV also exerted excellent synergistic lethality against leukemic bone marrow cells (BMC) at lower concentrations (0.1 μM) in combination with DNA methyltransferase (DNMT) inhibitor, decitabine. Considering the extermination of resilient LSC and synergism with decitabine, NV shows promise for clinical translation in the setting of a more tolerable and effective epigenetic targeted therapy for leukemia

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2015

A. Sasidharan, Sivaram, A. J., Retnakumari, A. P., Chandran, P., Malarvizhi, G. Loghanatha, Shantikumar V Nair, and Dr. Manzoor K., “Radiofrequency Ablation of Drug-Resistant Cancer Cells Using Molecularly Targeted Carboxyl-Functionalized Biodegradable Graphene”, Advanced Healthcare Materials, vol. 4, pp. 679-684, 2015.[Abstract]


Under ultralow radiofrequency (RF) power, transferrin-conjugated graphene nanoparticles can thermally ablate drug- or radiation-resistant cancer cells very effectively. The results suggest that graphene-based RF hyperthermia can be an efficient method to manage drug-/radiation-resistant cancers.

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2015

Dr. Jayakumar Rangasamy, S, S., P, C. K., H, A., P, J., and Shantikumar V Nair, “Periodontal Specific Differentiation of Dental Follicle Stem Cells into Osteoblast, Fibroblast and Cementoblast”, Tissue Engineering-C: Methods, vol. 21, no. 10, pp. 1044-1058, 2015.

2015

A. R. Kumar, Sivashanmugam, A., Deepthi, S., Iseki, S., Chennazhi, K. P., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Injectable Chitin-Poly(ε-caprolactone)/Nanohydroxyapatite Composite Microgels Prepared by Simple Regeneration Technique for Bone Tissue Engineering”, ACS Applied Materials & Interfaces, vol. 7, pp. 9399-9409, 2015.[Abstract]


Injectable gel systems, for the purpose of bone defect reconstruction, have many advantages, such as controlled flowability, adaptability to the defect site, and increased handling properties when compared to the conventionally used autologous graft, scaffolds, hydroxyapatite blocks, etc. In this work, nanohydroxyapatite (nHAp) incorporated chitin-poly(ε-caprolactone) (PCL) based injectable composite microgels has been developed by a simple regeneration technique for bone defect repair. The prepared microgel systems were characterized using scanning electron microscope (SEM), Fourier transformed infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The composite microgel, with the incorporation of nHAp, showed an increased elastic modulus and thermal stability and had shear-thinning behavior proving the injectability of the system. The protein adsorption, cytocompatibility, and migration of rabbit adipose derived mesenchymal stem cells (rASCs) were also studied. Chitin-PCL-nHAp microgel elicited an early osteogenic differentiation compared to control gel. The immunofluorescence studies confirmed the elevated expression of osteogenic-specific markers such as alkaline phosphatase, osteopontin, and osteocalcin in chitin-PCL-nHAp microgels. Thus, chitin-PCL-nHAp microgel could be a promising injectable system for regeneration of bone defects which are, even in deeper planes, irregularly shaped and complex in nature.

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2015

K. T. Shalumon, Deepthi, S., Anupama, M. S., Shantikumar V Nair, Dr. Jayakumar Rangasamy, and Chennazhi, K. P., “Fabrication of Poly (l-lactic acid)/gelatin Composite Tubular Scaffolds for Vascular Tissue Engineering”, International Journal of Biological Macromolecules, vol. 72, pp. 1048 - 1055, 2015.[Abstract]


The in vitro fabrication of fully functional 3D vascular tissue construct represents one of the most fundamental challenges in vascular tissue engineering. Polymer blending is an effective method for developing, desirable bio-composites for tissue engineering. This study employs the blending of desired characteristics of a synthetic polymer, poly (l-lactic acid) (PLLA) and a biopolymer, gelatin for enhancing cell adhesion sites. Aligned and random PLLA/gelatin nanofibers were fabricated using electrospinning technique. Morphological and chemical characterization of the nanofibrous scaffolds was carried out and the size of fibers ranged from 100 to 500nm. The SEM, fluorescent staining and viability assays revealed an increase in viability and proliferation of Human Umbilical Vein Endothelial Cells (HUVECs) and Smooth Muscle Cells (SMCs) proportional to gelatin content. The aligned fiber morphology helps cells to orient and elongate along their long axis. Thus the results were suggestive of the fact that topographically aligned nanofibrous scaffolds control cellular organization and possibly provide a good support for achieving the vital organization and physical properties of blood vessel.

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2015

Abhilash Sasidharan, Siddharth Swaroop, Chaitanya K. Koduri, Girish C. M., Parwathy Chandran, L.S. Panchakarla, Vijay H. Somasundaram, Genekehal S. Gowd, Shantikumar V Nair, and Dr. Manzoor K., “Comparative in Vivo Toxicity, Organ Biodistribution and Immune Response of Pristine, Carboxylated and PEGylated Few-layer Graphene Sheets in Swiss Albino Mice: A three month study”, Carbon, vol. 95, pp. 511 - 524, 2015.[Abstract]


We present a comprehensive 3 month report on the acute and chronic toxicity of intravenously administered (20&nbsp;mg&nbsp;kg−1) few-layer graphene (FLG) and, its carboxylated (FLG-COOH) and PEGylated (FLG-PEG) derivatives in Swiss albino mice. Whole-animal in&nbsp;vivo tracking studies revealed that irrespective of surface modifications, graphene predominantly accumulated in lungs over a period of 24&nbsp;h. Histological assessment and ex&nbsp;vivo confocal Raman spectral mapping revealed highest uptake and retention in lung tissue, followed by spleen, liver and kidney, with no accumulation in brain, heart or testis. FLG and FLG-COOH accumulated within organs induced significant cellular and structural damages to lungs, liver, spleen, and kidney, ranging from mild congestion to necrosis, fibrosis and glomerular filtration dysfunction, without appreciable clearance. Serum biochemistry analysis revealed that both FLG and FLG-COOH induced elevated levels of hepatic and renal injury markers. Quantitative RT-PCR studies conducted on 23 critical inflammation and immune response markers showed major alterations in gene expression profile by FLG, FLG-COOH and FLG-PEG treated animals. FLG-PEG in spite of its persistance within liver and spleen tissue for 3 months, did not induce any noticeable toxicity or organ damage, and displayed significant changes in Raman spectra, indicative of their biodegradation potential.

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2015

N. Vadera, Anusha Ashokan, Genekehal S. Gowd, Sajesh, K. M., Chauhan, R. P., Dr. Jayakumar Rangasamy, Shantikumar V Nair, and Dr. Manzoor K., “Manganese doped Nano-bioactive Glass for Magnetic Resonance Imaging”, Materials Letters, vol. 160, pp. 335 - 338, 2015.[Abstract]


Magnetic resonance imaging (MRI) is an attractive method to image biomaterial implants owing to its high spatial resolution and absence of ionizing radiation. However, most of the biomaterials lack magnetic contrast sufficient enough to be imaged in MRI. Here, we report synthesis of manganese doped nano-bioactive glass (Mn-nBG) giving bright contrast for MRI. We have optimized a room temperature method of doping nBG for efficient T1 weighted magnetic contrast. In vitro study using primary mesenchymal stem cells showed no toxicity for Mn-nBG up to a tested concentration of 100µg/ml, suggesting potential applications in cell labeling and tissue engineering.

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2015

Binulal Nelson Sathy, Dr. Ullas Mony, Dr. Deepthy Menon, VK, B., AG, M., and Shantikumar V Nair, “Bone Tissue Engineering with Multilayered Scaffolds-Part I: An Approach for Vascularizing Engineered Constructs In Vivo.”, Tissue Eng Part A., pp. 19-20, 2015.[Abstract]


Obtaining functional capillaries through the bulk has been identified as a major challenge in tissue engineering, particularly for critical-sized defects. In the present study, a multilayered scaffold system was developed for bone tissue regeneration, designed for through-the-thickness vascularization of the construct. The basic principle of this approach was to alternately layer mesenchymal stem cell-seeded nanofibers (osteogenic layer) with microfibers or porous ceramics (osteoconductive layer), with an intercalating angiogenic zone between the two and with each individual layer in the microscale dimension (100-400 μm). Such a design can create a scaffold system potentially capable of spatially distributed vascularization in the overall bulk tissue. In the cellular approach, the angiogenic zone consisted of collagen/fibronectin gel with endothelial cells and pericytes, while in the acellular approach, cells were omitted from the zone without altering the gel composition. The cells incorporated into the construct were analyzed for viability, distribution, and organization of cells on the layers and vessel development in vitro. Furthermore, the layered constructs were implanted in the subcutaneous space of nude mice and the processes of vascularization and bone tissue regeneration were followed by histological and energy-dispersive X-ray spectroscopy (EDS) analysis. The results indicated that the microenvironment in the angiogenic zone, microscale size of the layers, and the continuously channeled architecture at the interface were adequate for infiltrating host vessels through the bulk and vascularizing the construct. Through-the-thickness vascularization and mineralization were accomplished in the construct, suggesting that a suitably bioengineered layered construct may be a useful design for regeneration of large bone defects.

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2015

M. G. Sangeet Nair, Dr. Ullas Mony, Dr. Deepthy Menon, Dr. Manzoor K., Sidharthan, N., Pavithran, K., Shantikumar V Nair, and Krishnakumar N. Menon, “Development and molecular characterization of polymeric micro-nanofibrous scaffold of a defined 3-D niche for in vitro chemosensitivity analysis against acute myeloid leukemia cells”, International journal of nanomedicine, 2015.[Abstract]


Standard in vitro drug testing employs 2-D tissue culture plate systems to test anti-leukemic drugs against cell adhesion-mediated drug-resistant leukemic cells that harbor in 3-D bone marrow microenvironments. This drawback necessitates the fabrication of 3-D scaffolds that have cell adhesion-mediated drug-resistant properties similar to in vivo niches. We therefore aimed at exploiting the known property of polyurethane (PU)/poly-L-lactic acid (PLLA) in forming a micro-nanofibrous structure to fabricate unique, not presented before, as far as we are aware, 3-D micro-nanofibrous scaffold composites using a thermally induced phase separation technique. Among the different combinations of PU/PLLA composites generated, the unique PU/PLLA 60:40 composite displayed micro-nanofibrous morphology similar to decellularized bone marrow with increased protein and fibronectin adsorption. Culturing of acute myeloid leukemia (AML) KG1a cells in FN-coated PU/PLLA 60:40 shows increased cell adhesion and cell adhesion-mediated drug resistance to the drugs cytarabine and daunorubicin without changing the original CD34(+)/CD38(-)/CD33(-) phenotype for 168 hours compared to fibronectin tissue culture plate systems. Molecularly, as seen in vivo, increased chemoresistance is associated with the upregulation of anti-apoptotic Bcl2 and the cell cycle regulatory protein p27(Kip1) leading to cell growth arrest. Abrogation of Bcl2 activity by the Bcl2-specific inhibitor ABT 737 led to cell death in the presence of both cytarabine and daunorubicin, demonstrating that the cell adhesion-mediated drug resistance induced by Bcl2 and p27(Kip1) in the scaffold was similar to that seen in vivo. These results thus show the utility of a platform technology, wherein drug testing can be performed before administering to patients without the necessity for stromal cells.

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2015

B. Halima Shamaz, Anitha, A., Manju V., Kuttappan, S., Shantikumar V Nair, and Dr. Manitha B. Nair, “Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration”, Nanotechnology, vol. 26, no. 40, p. 405101, 2015.[Abstract]


Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)–polyvinyl alcohol (PVA) were incorporated into a gelatin–nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin–HA matrix. The incorporation of PLLA microfibers within the gelatin–nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics.

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2015

D. Narayanan, Shantikumar V Nair, and Dr. Deepthy Menon, “A Systematic Evaluation of Hydroxyethyl Starch as a Potential Nanocarrier for Parenteral Drug Delivery”, International Journal of Biological Macromolecules, vol. 74, pp. 575-584, 2015.[Abstract]


Development of parenteral nanoformulations is highly challenging due to the stringent demands on stability, reproducibility and high drug loading with minimal excipients. This study focuses on the development of a pharmaceutically acceptable nanomatrix system for parenteral delivery based on Hydroxyethyl Starch (HES), a FDA approved polymer that is relatively unexplored in drug delivery research. HES nanoparticles were prepared through a simple, two-step crosslinking-precipitation route, yielding 160. ±. 5. nm, nearly monodispersed spherical particles with high colloidal stability. The utility of this nanocarrier for parenteral delivery was verified by a panel of hemo/cytocompatibility assays at high concentrations (0.05-1. mg/ml) in vitro and in vivo. HES nanomatrix was found effective in encapsulating two chemically distinct drugs having varying hydrophobicities, with the release behavior being influenced by their chemical nature and drug-matrix interactions. Better in vitro efficacy was measured for the nanoencapsulated drug than its bare form, establishing the potential of HES nanocarriers for controlled drug delivery. © 2014 Elsevier B.V.

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2015

Dr. Manitha B. Nair, Nancy, D., Krishnan, A. G., Anjusree, G. S., Vadukumpully, S., and Shantikumar V Nair, “Graphene oxide nanoflakes incorporated gelatin–hydroxyapatite scaffolds enhance osteogenic differentiation of human mesenchymal stem cells”, Nanotechnology, vol. 26, p. 161001, 2015.[Abstract]


In this study, graphene oxide (GO) nanoflakes (0.5 and 1 wt%) were incorporated into a gelatin–hydroxyapatite (GHA) matrix through a freeze drying technique and its effect to enhance mechanical strength and osteogenic differentiation was studied. The GHA matrix with GO demonstrated less brittleness in comparison to GHA scaffolds. There was no significant difference in mechanical strength between GOGHA 0.5 and GOGHA 1.0 scaffolds. When the scaffolds were immersed in phosphate buffered saline (to mimic physiologic condition) for 60 days, around 50–60% of GO was released in sustained and linear manner and the concentration was within the toxicity limit as reported earlier. Further, GOGHA 0.5 scaffolds were continued for cell culture experiments, wherein the scaffold induced osteogenic differentiation of human adipose derived mesenchymal stem cells without providing supplements like dexamethasone, L-ascorbic acid and β glycerophosphate in the medium. The level of osteogenic differentiation of stem cells was comparable to those cultured on GHA scaffolds with osteogenic supplements. Thus biocompatible, biodegradable and porous GO reinforced gelatin–HA 3D scaffolds may serve as a suitable candidate in promoting bone regeneration in orthopaedics.

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2015

P. Pillai, Surenya, R. S., Shantikumar V Nair, and Lakshmanan, V. - K., “Cancer kinases and its novel inhibitors: Past, present and future challenges”, Current Drug Targets, vol. 16, pp. 1233-1245, 2015.[Abstract]


Cancer kinome is now well organized as an important target for a new class of cancer drugs. There are more than 500 members in the kinase family in which some of them are clinically analysed, while the rest are under investigation for potential therapeutic applications. Phosphorylation, major function of kinases is one of the most significant signal transduction mechanism in which intercellular signals regulate intracellular processes like ion transport, hormone responses and cellular proliferation. Any deregulation of kinase function may lead to tumor progression and other disorders such as immu-nological, neurological, metabolic including also infectious diseases. This led to the necessity in the development of kinase inhibitors as therapeutic agent. Herein we discuss about different types of kinases and their inhibitors in various types of cancers. This review portrays a broad overview of the origin of kinases, discovery, the characterization and mode of action of kinase inhibitors in cancer therapy. © 2015 Bentham Science Publishers.

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2015

M. Janani, Srikrishnarka, P., Shantikumar V Nair, and Nair, A. S., “An in-depth review on the role of carbon nanostructures in dye-sensitized solar cells”, Journal of Materials Chemistry A, vol. 3, pp. 17914-17938, 2015.[Abstract]


Dye-sensitized solar cells (DSSCs) are considered to be promising, low-cost alternatives to amorphous silicon solar cells. The major components of a DSC include a metal oxide (usually TiO2), a dye, an electrolyte and a Pt- or carbon-deposited counter electrode. The photoexcited electrons from the dye diffuse through the TiO2 network and reach the counter electrode through an external circuit. However due to the trap-limited diffusion process, the electron collection efficiency is affected. Thus, for a hassle-free transport of electrons there is a need for additional electron transport channels. Further in order to reduce the overall cost of the device there is also a need for cheaper alternative counter electrodes in place of Pt. The 15th most abundant element in the earth's crust, carbon and its allotropes with their outstanding catalytic activity and electrical conductivity prove to be promising materials to overcome all these shortcomings and demerits. The review presented below summarizes the up-to-date research efforts on the role of carbon nanostructures in DSSCs, the various synthesis strategies adopted for their preparation and their photovoltaic performance. The review also includes a brief discussion about the role of carbon nanostructures in non-planar flexible wire-shaped DSSCs. © The Royal Society of Chemistry 2015.

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2015

J. Joseph, Shantikumar V Nair, and Dr. Deepthy Menon, “Integrating Substrateless Electrospinning with Textile Technology for Creating Biodegradable Three-Dimensional Structures”, Nano letters, vol. 15, pp. 5420–5426, 2015.[Abstract]


The present study describes a unique way of integrating substrateless electrospinning process with textile technology. We developed a new collector design that provided a pressure-driven, localized cotton-wool structure in free space from which continuous high strength yarns were drawn. An advantage of this integration was that the textile could be drug/dye loaded and be developed into a core–sheath architecture with greater functionality. This method could produce potential nanotextiles for various biomedical applications.

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2015

Jipnomon Joseph, Paravannoor, A., Shantikumar V Nair, Han, Z. J., Ostrikov, Kb, and Balakrishnan, A., “Supercapacitors based on camphor-derived meso/macroporous carbon sponge electrodes with ultrafast frequency response for ac line-filtering”, Journal of Materials Chemistry A, vol. 3, pp. 14105-14108, 2015.[Abstract]


Supercapacitor electrodes assembled from meso/macroporous camphor-derived carbon sponges show highly promising performance in ac line-filtering. The coin-type supercapacitor exhibits an ultrafast frequency response with a phase angle of -78°and a RC time constant of 319 μs at 120 Hz and may be a viable alternative to the presently dominant aluminium electrolytic capacitors. © The Royal Society of Chemistry 2015.

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2015

A. Sivashanmugam, R. Kumar, A., M. Priya, V., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “An Overview of Injectable Polymeric Hydrogels for Tissue Engineering”, European Polymer Journal, vol. 72, pp. 543-565, 2015.[Abstract]


The desire and need to minimize traditional open surgeries is gearing up as it could reduce the healthcare expenses and improve the recovery time for the patients. Minimal invasive procedures using endoscopes, catheters and needles have been developed considerably in the last few decades. In the field of tissue engineering and regenerative medicine, there is a need for advancement over the conventional scaffolds and pre-formed hydrogels. In this scenario, injectable hydrogels have gained wider appreciation among the researchers, as they can be used in minimally invasive surgical procedures. Injectable gels with their ease of handling, complete filling of the defect area and good permeability have emerged as promising biomaterials. The system can effectively deliver a wide array of therapeutic agents like drugs, growth factors, fillers and even cells. This review provides an overview of the recent trends in the preparation of injectable hydrogels, along with key factors to be kept in balance for designing an effective injectable hydrogel system. Further, we have summarized the application of injectable hydrogels in adipose, bone, cartilage, intervertebral discs and muscle tissue engineering. © 2015 Elsevier Ltd.

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2015

S. Nandan, Deepak, T. G., Shantikumar V Nair, and Sreekumaran A Nair, “TiO2 Nanofibers Resembling 'Yellow Bristle Grass' in Morphology by a Soft Chemical Transformation”, Dalton Transactions, vol. 44, pp. 9637-9645, 2015.[Abstract]


We synthesized a uniquely shaped one-dimensional (1-D) TiO2 nanostructure having the morphology of yellow bristle grass with high surface area by the titanate route under mild reaction conditions. The electrospun TiO2-SiO2 composite nanofibers upon treatment with concentrated NaOH at 80 °C under ambient pressure for 24 h resulted in sodium titanate (Na2Ti3O7) nanostructures. The Na2Ti3O7 nanostructures have an overall 1-D fibrous morphology but the highly porous fiber surfaces were decorated with layered thorn-like features (a morphology resembling that of yellow bristle grass) resulting in high surface area (113 m2 g-1) and porosity. The Na2Ti3O7 nanostructures were converted into TiO2 nanostructures of the same morphology by acidification (0.1 N HCl) followed by low temperature sintering (110°C) processes. Dye-sensitized solar cells (DSCs) constructed out of the material (cells of area 0.20 cm2 and thickness 12 μm) showed a power conversion efficiency (η) of 8.02% in comparison with commercial P-25 TiO2 (η = 6.1%). © The Royal Society of Chemistry 2015.

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2015

A. M. Cherian, Snima, K. S., Kamath, C. R., Shantikumar V Nair, and Lakshmanan, V. K., “Effect of Baliospermum Montanum Nanomedicine Apoptosis Induction and Anti-migration of Prostate Cancer Cells”, Biomedicine and Pharmacotherapy, vol. 71, pp. 201-209, 2015.[Abstract]


Prostate cancer has been diagnosed as the second most frequent and the sixth among the cancer causing deaths among men worldwide. There is a limited scope for the prevalent therapies as prostate cancer advances and they present adverse aftermaths that have put way for us to delve into naturally available anticancer agents. The main objective of the present work is to compile the advantages of ayurvedic herbal formulations with modern technology. Baliospermum montanum is a plant that is used in ayurveda for the treatment of cancer and the plant is studied to possess various constituents in it that are responsible for its anticancer activity. Stable nanoparticles of B. montanum were prepared from both the aqueous and ethanolic extracts of the plant and its cytotoxic effects were studied on prostate cancer and normal cell lines. Size analysis by DLS and SEM revealed the average size of nanoparticles prepared was 100 ± 50. nm and 150 ± 50. nm for the nanoparticles prepared from aqueous and ethanolic extract respectively. In vitro cytotoxicity showed a concentration and time dependent toxicity on prostate cancer cells with cell viability of 22% and 6% with maximum concentration of aqueous and ethanolic nanoparticles respectively, in 48. h. In vitro hemolysis assay confirmed that the prepared nanoparticles were compatible with blood with no occurrence of hemolysis. The nanoparticles showed a significant reduction in the colony forming ability and wound healing capacity of the prostate cancer cells. These studies hold the anti cancer potential of the B. montanum nanoparticles making it an important candidate for prostate cancer therapy. © 2015 Elsevier Masson SAS.

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2015

K. H. Anupriya, Ranjusha, R., Shantikumar V Nair, Balakrishnan, A., and Subramanian, K. R. V., “Defining role of the Surface and Bulk Contributions in Camphoric Carbon Grafted Lithium Nickel Manganese Oxide Powders for Lithium ion Batteries”, Ceramics International, vol. 41, pp. 3269-3276, 2015.[Abstract]


In the present study, lithium nickel manganese oxide powders grafted with camphoric nano-carbons have been exploited to fabricate high voltage, high capacity rechargeable electrodes for Li storage. The prepared lithium nickel manganese oxide particles were pyrolyzed using a camphoric solution to graft porous camphoric carbon layer on to the surface. A detailed study was performed to elucidate the effect of carbon content on the performance of the electrode. Relative contributions of capacitive and diffusion-controlled processes underlying these composite electrodes have been mathematically modeled. The lithium nickel manganese oxide composites showed two times higher conductivity as compared to the pristine samples. These electrodes exhibited a specific capacity value of  154 mAhg-1 and showed good rate capability. The capacity fading was found to be  17% at the end of 200 cycles for 100% depth of discharge. The specific capacity and capacity retention for these blends were found to be  10% and  40% higher respectively than pristine powders which are promising considering their low cost and facile fabrication process. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

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2015

R. Ranjusha, Sonia, T. S., Lakshmi, V., Roshny, S., Kalluri, S., Kim, T. N., Shantikumar V Nair, and Balakrishnan, A., “Synthesis, Characterization and Rate Capability Performance of the Micro-porous MnO2 Nanowires as Cathode Material in Lithium Batteries”, Materials Research Bulletin, vol. 70, pp. 1-6, 2015.[Abstract]


A peculiar architecture of one-dimensional MnO<inf>2</inf> nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 102. Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g-1 and 200 W kg-1, respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells. © 2015 Elsevier Ltd. All rights reserved.

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2015

A. Paravannoor, Shantikumar V Nair, Pattathil, P., Manca, M., and Balakrishnan, A., “High Voltage Supercapacitors based on Carbon-Grafted NiO Nanowires Interfaced with an Aprotic Ionic Liquid”, Chemical Communications, vol. 51, pp. 6092-6095, 2015.[Abstract]


The report provides a preliminary assessment of the charge storage prerogatives of an asymmetric electrochemical capacitor employing a carbon-grafted NiO electrode interfaced with 1-ethyl-3-methyl imidazoliumdicyanamide as an ionic liquid electrolyte. This configuration has been demonstrated to be potentially exploited for developing hybrid supercapacitors providing as high energy density as 21 W h Kg-1.

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2015

A. S. Pillai, Rajagopalan, R., Joseph, J., Amruthalakshmi, A., Ajay, A., Shakir, I., Shantikumar V Nair, and Balakrishnan, A., “Mesoscopic Architectures of Co(OH)2 Spheres with an Extended Array of Microporous Threads as Pseudocapacitor Electrode Materials”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 470, pp. 280-289, 2015.[Abstract]


The present study demonstrates a low temperature hydrothermal route for the synthesis of α-cobalt hydroxide comprising of randomly arrayed nano strands in a three dimensional plane. These micro/nano hybrid structures were used as building blocks for processing high surface area supercapacitor electrodes. Surface area of these structures was measured to be  100m2g-1. The influence of surface morphology in three different electrolytes namely lithium hydroxide, sodium hydroxide and potassium hydroxide was analyzed. The influence of surface morphology on capacitance and internal resistance was also determined and explained on the basis of redox reactions in these electrolytes. Capacitance values as high as 1024Fg-1 was attained for these structures when employed as thin film electrodes with life extending to more than 5000 cycles. Inductively coupled plasma-atomic emission spectroscopy was used to determine the electrode dissolution in the given electrolyte and the observations were co-related with the cycling stability. Low self-discharge, high rate capability along with low cost makes them promising systems for supercapacitor applications. © 2015 Elsevier B.V.

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2014

Dr. Sahadev Shankarappa, Dr. Manzoor K., and Shantikumar V Nair, “Efficacy versus Toxicity - The Yin and Yang in translating nanomedicines,”, Nanomaterials and Nanotechnology, vol. 4, no. 23, 2014.[Abstract]


Nanomedicine, as a relatively new offshoot of nanotechnology, has presented vast opportunities in biomedical research for developing novel strategies to treat diseases. In the past decade, there has been a significant increase in in vitro and preclinical studies addressing the benefits of nanomedicines. In this commentary, we focus specifically on the efficacy- and toxicity-related translational challenges of nanocarrier-mediated systems, and briefly discuss possible strategies for addressing such issues at in vitro and preclinical stages. We address questions related specifically to the balance between toxicity and efficacy, a balance that is expected to be substantially different for nanomedicines compared to that for a free drug. Using case studies, we propose a ratiometric assessment tool to quantify the overall benefit of nanomedicine as compared to free drugs in terms of efficacy and toxicity. The overall goal of this commentary is to emphasize the strategies that promote the translation of nanomedicines, especially by learning lessons from previous translational failures of other drugs and devices, and to apply these lessons to critically assess data at the basic stages of nanomedicinal research.

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2014

N. Ganesh, Anusha Ashokan, R kannan, R., Chennazhi, K., Shantikumar V Nair, and Dr. Manzoor K., “Magnetic Resonance Functional Nano-hydroxyapatite Incorporated Poly(caprolactone) Composite Scaffolds for in Situ Monitoring of Bone Tissue Regeneration by MRI”, Tissue Engineering - Part A, vol. 20, pp. 2783-2794, 2014.[Abstract]


In this study, we have reported the incorporation of a multi-modal contrast agent based on hydroxyapatite nanocrystals, within a poly(caprolactone)(PCL) nanofibrous scaffold by electrospinning. The multifunctional hydroxyapatite nanoparticles (MF-nHAp) showed simultaneous contrast enhancement for three major molecular imaging techniques. In this article, the magnetic resonance (MR) contrast enhancement ability of the MF-nHAp was exploited for the purpose of potentially monitoring as well as for influencing tissue regeneration. These MF-nHAp containing PCL scaffolds were engineered in order to enhance the osteogenic potential as well as its MR functionality for their application in bone tissue engineering. The nano-composite scaffolds along with pristine PCL were evaluated physico-chemically and biologically in vitro, in the presence of human mesenchymal stem cells (hMSCs). The incorporation of 30-40 nm sized MF-nHAp within the nanofibers showed a substantial increase in scaffold strength, protein adsorption, proliferation, and osteogenic differentiation of hMSCs along with enhanced MR functionality. This preliminary study was performed to eventually exploit the MR contrast imaging capability of MF-nHAp in nanofibrous scaffolds for real-time imaging of the changes in the tissue engineered construct. © Copyright 2014, Mary Ann Liebert, Inc.

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2014

P. Chandran, Kavalakatt, A., Malarvizhi, G. L., Vasanthakumari, D. R. V. N., Retnakumari, A. P., Sidharthan, N., Pavithran, K., Shantikumar V Nair, and Koyakutty, M., “Epigenetics Targeted Protein-Vorinostat Nanomedicine Inducing Apoptosis in Heterogeneous Population of Primary Acute Myeloid Leukemia Cells Including Refractory and Relapsed Cases”, Nanomedicine: Nanotechnology, Biology, and Medicine, vol. 10, pp. 721-732, 2014.[Abstract]


Aberrant epigenetics play a key role in the onset and progression of acute myeloid leukemia (AML). Herein we report in silico modelling based development of a novel, protein-vorinostat nanomedicine exhibiting selective and superior anti-leukemic activity against heterogeneous population of AML patient samples (n=9), including refractory and relapsed cases, and three representative cell lines expressing CD34+/CD38- stem cell phenotype (KG-1a), promyelocytic phenotype (HL-60) and FLT3-ITD mutation (MV4-11). Nano-vorinostat having  100nm size exhibited enhanced cellular uptake rendering significantly lower IC50 in AML cell lines and patient samples, and induced enhanced HDAC inhibition, oxidative injury, cell cycle arrest and apoptosis compared to free vorinostat. Most importantly, nanomedicine showed exceptional single-agent activity against the clonogenic proliferative capability of bone marrow derived leukemic progenitors, while remaining non-toxic to healthy bone marrow cells. Collectively, this epigenetics targeted nanomedicine appears to be a promising therapeutic strategy against various French-American-British (FAB) classes of AML. From the Clinical Editor: Through the use of a protein-vorinostat agent, exceptional single-agent activity was demonstrated against the clonogenic proliferative capability of bone marrow derived leukemic progenitors, while remaining non-toxic to healthy bone marrow cells. The studied epigenetics targeted nanomedicine approach is a promising therapeutic strategy against various French-American-British classes of acute myeloid leukemia. © 2014 Elsevier Inc.

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2014

J. Aswathy, Seethalekshmy, N. V., Hiran, K. R., Bindhu, M. R., Manzoor, K., Shantikumar V Nair, and Menon, D., “Mn-doped Zinc Sulphide Nanocrystals for Immunofluorescent Labeling of Epidermal Growth Factor Receptors on Cells and Clinical Tumor Tissues”, Nanotechnology, vol. 25, 2014.[Abstract]


The field of molecular detection and targeted imaging has evolved considerably with the introduction of fluorescent semiconductor nanocrystals. Manganese-doped zinc sulphide nanocrystals (ZnS:Mn NCs), which are widely used in electroluminescent displays, have been explored for the first time for direct immunofluorescent (IF) labeling of clinical tumor tissues. ZnS:Mn NCs developed through a facile wet chemistry route were capped using amino acid cysteine, conjugated to streptavidin and thereafter coupled to biotinylated epidermal growth factor receptor (EGFR) antibody utilizing the streptavidin-biotin linkage. The overall conjugation yielded stable EGFR antibody conjugated ZnS:Mn NCs (EGFR ZnS:Mn NCs) with a hydrodynamic diameter of 65 ± 15 nm, and having an intense orange-red fluorescence emission at 598 nm. Specific labeling of EGF receptors on EGFR+ve A431 cells in a co-culture with EGFR-ve NIH3T3 cells was demonstrated using these nanoprobes. The primary antibody conjugated fluorescent NCs could also clearly delineate EGFR over-expressing cells on clinical tumor tissues processed by formalin fixation as well as cryopreservation with a specificity of 86% and accuracy of 88%, in comparison to immunohistochemistry. Tumor tissues labeled with EGFR ZnS:Mn NCs showed good fluorescence emission when imaged after storage even at 15 months. Thus, ZnS nanobioconjugates with dopant-dependent and stable fluorescence emission show promise as an efficient, target-specific fluorophore that would enable long term IF labeling of any antigen of interest on clinical tissues. © 2014 IOP Publishing Ltd.

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2014

J. Joseph, Rajagopalan, R., Anoop, S. S., Amruthalakshmi, V., Ajay, A., Balakrishnan, A., and Shantikumar V Nair, “Shape Tailored Ni3(NO3)2(OH)4 Nano-Flakes Simulating 3-D Bouquet-like Structures for Supercapacitors: Exploring the Effect of Electrolytes on stability and Performance”, RSC Advances, vol. 4, pp. 39378-39385, 2014.[Abstract]


The present study demonstrates a novel, low temperature synthetic approach by which 3-D bouquets of nickel hydroxide nitrate were processed into high surface area electrodes for supercapacitor applications. The synthesized micro-bouquets comprised randomly arrayed microporous nanoflakes (pore size: 2-6 nm) and exhibited a surface area of 150 m2 g-1. Morphological evolution studies were performed to elucidate how surface morphology of these electrode materials affect redox reactions and their ultimate performance as a supercapacitor. The electrodes were tested in three different electrolytes, namely lithium hydroxide, potassium hydroxide and sodium hydroxide. From the detailed electrochemical analysis, an intrinsic correlation between the capacitance, internal resistance and the surface morphology was deduced and explained on the basis of relative contributions from the faradaic properties in different electrolytes. Depending on the surface morphology and electrolyte incorporated, these nano/micro-hybrid electrodes exhibited specific mass capacitance value of as high as 1380 ± 38 F g-1. Inductively coupled plasma-atomic emission spectroscopy was used to determine the electrode dissolution in the given electrolyte and the findings were co-related with the cycling stability. By employing this low cost electrode design, high stability (&gt;5000 cycles with no fading) was achieved in lithium hydroxide electrolyte. Furthermore, a working model supercapacitor in a coin cell form is also shown to exhibit peak power and energy density of 3 kW kg -1 and 800 mW h kg-1, respectively. © 2014 the Partner Organisations.

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2014

D. Jacob, Mini, P. A., Balakrishnan, A., Shantikumar V Nair, and Subramanian, K. R. V., “Electrochemical Behaviour of Graphene-poly (3,4-ethylenedioxythiophene) (PEDOT) Composite Electrodes for Supercapacitor Applications”, Bulletin of Materials Science, vol. 37, pp. 61-69, 2014.[Abstract]


In this paper, we report on the electrochemical characteristics of graphene-PEDOT composite electrodes. The electrodes were made of indium tin oxide (ITO) substrates by simple processes of electrophoretic deposition of graphene followed by electropolymerization of EDOT monomer. The composite electrode was obtained by electrochemical measurements, a median specific capacitance of 1410 F/g and a median area capacitance of 199 mF cm-2 at a scan rate of 40 mVs-1. The composite showed good stability characteristics after repeated scans in cyclic voltammmetry and faredmuch better than a thin film of PEDOT. The thermal stability of the composite is also much superior when compared to the polymer with a weight loss temperature of 350 °C for the composite and 250 °C for the polymer, respectively. The above electrochemical and thermal behaviours of the composite are correlated to the unique morphology of electrodeposited graphene that provides a conductive and high surface area template for electropolymerization. © Indian Academy of Sciences.

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2014

T. G. Deepak, Anjusree, G. S., Pai, K. R. N., Subash, D., Shantikumar V Nair, and Nair, A. S., “Cabbage Leaf-shaped Two-Dimensional TiO2 Mesostructures for Efficient Dye-sensitized Solar Cells”, RSC Advances, vol. 4, pp. 27084-27090, 2014.[Abstract]


We have fabricated 'cabbage leaf'-like TiO2 mesostructures of high surface area from electrospun TiO2-SiO2 composite nanofibers by titanate route for dye-sensitized solar cell (DSC) application. The initial TiO2-SiO2 composite nanofibers, the intermediate titanate and the final leaf-like TiO2 are characterized by spectroscopy, microscopy and surface area measurements. The material (final TiO2) acts as a dual functional material in DSCs with high dye loading and a high light scattering capability. The best DSC (a square-shaped cell of area 0.20 cm2 and thickness of 12 μm) fabricated out of the material showed a superior photovoltaic performance with an efficiency (η) of 7.92% in comparison to that of commercial P25 TiO2 (6.50%). This journal is © the Partner Organisations 2014.

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2014

S. Fazal, Jayasree, A., Sasidharan, S., Menon, D., Koyakutty, M., and Shantikumar V Nair, “Green synthesis of anisotropic gold nanoparticles for photothermal therapy of cancer”, ACS Applied Materials and Interfaces, vol. 6, pp. 8080-8089, 2014.[Abstract]


Nanoparticles of varying composition, size, shape, and architecture have been explored for use as photothermal agents in the field of cancer nanomedicine. Among them, gold nanoparticles provide a simple platform for thermal ablation owing to its biocompatibility in vivo. However, the synthesis of such gold nanoparticles exhibiting suitable properties for photothermal activity involves cumbersome routes using toxic chemicals as capping agents, which can cause concerns in vivo. Herein, gold nanoparticles, synthesized using green chemistry routes possessing near-infrared (NIR) absorbance facilitating photothermal therapy, would be a viable alternative. In this study, anisotropic gold nanoparticles were synthesized using an aqueous route with cocoa extract which served both as a reducing and stabilizing agent. The as-prepared gold nanoparticles were subjected to density gradient centrifugation to maximize its NIR absorption in the wavelength range of 800-1000 nm. The particles also showed good biocompatibility when tested in vitro using A431, MDA-MB231, L929, and NIH-3T3 cell lines up to concentrations of 200 μg/mL. Cell death induced in epidermoid carcinoma A431 cells upon irradiation with a femtosecond laser at 800 nm at a low power density of 6 W/cm2 proved the suitability of green synthesized NIR absorbing anisotropic gold nanoparticles for photothermal ablation of cancer cells. These gold nanoparticles also showed good X-ray contrast when tested using computed tomography (CT), proving their feasibility for use as a contrast agent as well. This is the first report on green synthesized anisotropic and cytocompatible gold nanoparticles without any capping agents and their suitability for photothermal therapy. © 2014 American Chemical Society.

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2014

V. Lakshmi, Ranjusha, R., Vineeth, S., Balakrishnan, A., and Shantikumar V Nair, “Supercapacitors based on microporous β-Ni(OH)2 nanorods”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 457, pp. 462-468, 2014.[Abstract]


A peculiar architecture of a novel class one dimensional β-Ni(OH)2 nanorods synthesized by an optimized surfactant-free aqueous precipitation route has been lucratively exploited to fabricate highly efficient microporous electrodes for supercapacitors. These fabricated electrodes comprised of a highly porous overlay of interconnected nanoscale units with rod-shaped profile which terminates into jagged-like morphology. The surface area of these nanorods was found to be  91m2g-1. This architecture transcribes into a superior cycling performance (capacitance of 1150Fg-1 was achieved) with more than 99% of the initial capacitance being retained after 5000 charging/discharging cycles. Their outstanding intercalation/de-intercalation prerogatives have also been exploited to fabricate supercapacitor coin cells which reveal a significant power density of 52kWkg-1 and energy density of 4Whkg-1 with extremely fast response time of 1.2ms. © 2014 Elsevier B.V.

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2013

, K.V., S., G., R., Shantikumar V Nair, K.R.V, S., and V.-K., L., “Development of activated carbon-ceria nanocomposite materials for prostate cancer therapy”, Advanced Science, Engineering and Medicine, 2013.[Abstract]


Using electrophoretic co-deposition (EPD), nanocomposite of ball-milled activated carbon and cerium (IV) oxide (CeO2) (or) ceria was prepared as a thin film. Nanocomposite preparation was done and deposited on aluminium foil. Phase analyses were carried out using X-ray diffraction analysis (XRD) showing the uniform compositional profile of the composite. The elemental analysis of ceria, oxygen and carbon was carried out using X-ray photoelectron spectroscopy (XPS). Detailed scanning electron microscopy analysis showed that ball-milled activated carbon, ceria and carbon-ceria composite were formed on the nanoscale and uniformly distributed. The toxicity of activated carbon ceria nanocomposite towards the prostate cancer cell line was evaluated and found to be toxic towards prostate cancer cell lines (PC-3) as analyzed by MTT assay.

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2013

Sowmya S, Jayakumar R., and Shantikumar V Nair, “Advantages of chitin-based nanobiomaterials in nanomedicine”, Marine Biomaterials: Characterization, Isolation and Applications, 2013.[Abstract]


The Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO, 2008) have recognized a need for scientic advice on any food safety implications that may arise from the use of nanotechnologies in the food and agriculture

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2013

S. Chandran, Praveen, G., Snima, K. S., Pavithran, K., Chennazhi, K., Lakshmanan, V. K., and Shantikumar V Nair, “Potential use of drug loaded nano composite pectin scaffolds for the treatment of ovarian cancer.”, Current drug delivery, vol. 10, pp. 326-335, 2013.[Abstract]


Ovarian cancer is the ninth most common cancer amongst women and ranked as fifth in terms of the cause of cancer related mortality accounting for more deaths than any other cancer of the female reproductive system. Gemcitabine is the most common chemotherapeutic agent used in the treatment of ovarian cancer despite of its disadvantage of having a very lesser half life. In this study, we have envisaged the use of a highly porous, biomimetic and implantable pectin scaffold embedded with gemcitabine loaded fibrin nanoconstructs to improve the half life of the drug, thereby providing localized therapy for ovarian cancer. The controlled and sustained release of the chemokine from the scaffold system was extensively analyzed in vitro different pH environments. The composite scaffolds were found to be highly biocompatible when tested with mammalian cell lines. The excellent cytotoxicity and apoptosis responses induced in ovarian cancer, PA- 1 cell lines proved that the nanocomposite Pectin scaffolds loaded with specific chemokine can be used as implantable "therapeutic wafers" for distracting metastatic cancer cells and thus improve the survival rate of ovarian cancer afflicted individuals.

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2013

T. R. Anuraj, N Rejinold, S., Biswas, R., Saroj, S., Shantikumar V Nair, Dr. Jayakumar Rangasamy, and Dr. Sabitha M., “Curcumin Nanospheres by Surfactant Free Wet Milling Method (In Press)”, Journal of Biomedical Nanotechnology, 2013.

2013

A. Paravannoor, Ranjusha, R., Sivakumar, N., Asha, A. M., Kim, T. N., Shantikumar V Nair, Vani, R., Kalluri, S., Balakrishnan, A., and Subramanian, K. R. V., “Chemical and Structural Stability of Porous Thin Film NiO Nanowire Based Electrodes for Supercapacitors”, Chemical Engineering Journal, vol. 220, pp. 360-366, 2013.[Abstract]


Nanowires of NiO were successfully synthesized using a simple hydrothermal route. The nanowires were characterized for phase composition and morphology by X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques, respectively. XRD analysis showed that the powders produced were of high purity cubic NiO phase. Selected area electron diffraction (SAED) analysis during TEM showed the growth direction of NiO nanowires in (100), while exhibiting an average diameter of ∼ 65nm. BET analysis showed these nanowires exhibiting a surface area of 153.2m2/g. These nanowires were electrophoretically deposited on titanium foils as thin layer (∼5μm thickness) and were studied for their capacitive behavior as electrodes for supercapacitor applications. Image analysis and atomic force microscopy (AFM) studies revealed the thin film coating to be highly porous (&gt;50%). Cyclic voltammetry (CV) studies on these electrodes exhibited a specific mass capacitance of 750F/g with 12% capacitance fade at the end of 1000 cycles. The present study elucidates how NiO surface morphology and OH- adsorption/desorption behaviors underlying these electrodes impact the chemical and structural stability performance. © 2013 Elsevier B.V.

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2013

N. Ganesh, Hanna, C., Nair, L. S., and Shantikumar V Nair, “Enzymatically Cross-linked Alginic-hyaluronic Acid Composite Hydrogels as Cell Delivery Vehicles”, International Journal of Biological Macromolecules, vol. 55, pp. 289-294, 2013.[Abstract]


An injectable composite gel was developed from alginic and hyaluronic acid. The enzymatically cross-linked injectable gels were prepared via the oxidative coupling of tyramine modified sodium algiante and sodium hyaluronate in the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H2O2). The composite gels were prepared by mixing equal parts of the two tyraminated polymer solutions in 10U HRP and treating with 1.0% H2O2. The properties of the alginate gels were significantly affected by the addition of hyaluronic acid. The percentage water absorption and storage modulus of the composite gels were found to be lower than the alginate gels. The alginate and composite gels showed lower protein release compared to hyaluronate gels in the absence of hyaluronidase. Even hyaluronate gels showed only approximately 10% protein release after 14 days incubation in phosphate buffer solution. ATDC-5 cells encapsulated in the injectable gels showed high cell viability. The composite gels showed the presence of enlarged spherical cells with significantly higher metabolic activity compared to cells in hyaluronic and alginic acid gels. The results suggest the potential of the composite approach to develop covalently cross-linked hydrogels with tuneable physical, mechanical, and biological properties. © 2013 Elsevier B.V.

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2013

P. R. Sreerekha, Shantikumar V Nair, Chennazhi, K. P., and Menon, D., “Fabrication of Electrospun Poly (lactide-co-glycolide)-fibrin Multiscale Scaffold for Myocardial Regeneration in Vitro”, Tissue Engineering - Part A, vol. 19, pp. 849-859, 2013.[Abstract]


Myocardial tissue engineering is one of the most promising treatment strategies to restore heart function after a massive heart attack. The biomaterials, cells, and scaffold design play important roles in engineering of heart tissue. In this study, we have developed a fibrin-based multiscale electrospun composite scaffold for myocardial regeneration. Fibrin is the natural wound-healing matrix having angiogenic potential and comprehensively used for tissue engineering applications. It provides a natural environment for cell attachment, migration, and proliferation. Morphological, chemical, and mechanical characterization of the scaffolds was done by scanning electron microscopy, fibrin-specific phosphotungstic acid hematoxylin staining, and mechanical testing. The fiber diameters of fibrin nanofibers range from 50 to 300 nm and that of poly (lactide-co-glycolide) microfibers range from 2 to 4 μm, which mimics the structural hierarchy of native myocardial tissue. Our results indicate that this scaffold enhances the differentiation of mesenchymal stem cells into cardiomyocytes. The cardiac phenotype of the cells was confirmed by the presence of cardiac-specific proteins like α-sarcomeric actinin, troponin, tropomyosin, desmin, and atrial natriuretic peptide Estimation of D-Dimer in the culture supernatant for 2 weeks and analysis of scaffold for 3 weeks of in vitro culture of cardiomyocytes indicated the degradation of fibrin and presence of newly synthesized collagen respectively. Our results demonstrate the promising potential of this scaffold for myocardial tissue engineering applications. © Copyright 2013, Mary Ann Liebert, Inc. 2013.

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2013

P. R. Sreerekha, Menon, D., Shantikumar V Nair, and Chennazhi, K. P., “Fabrication of fibrin based electrospun multiscale composite scaffold for tissue engineering applications”, Journal of Biomedical Nanotechnology, vol. 9, pp. 790-800, 2013.[Abstract]


Fabricating scaffolds mimicking the native extracellular matrix (ECM) in both structure and function is a key challenge in the field of tissue engineering. Previously we have demonstrated a novel electrospinnig method for the fabrication of fibrin nanofibers using Poly(vinyl alcohol) (PVA) as an 'electrospinning-driving' polymer. Here we demonstrate the fabrication and characterization of a multiscale fibrin based composite scaffold with polycaprolactone (PCL) by sequential electrospinning of PCL microfibers and fibrin nanofibers. This multiscale scaffold has great potential for tissue engineering applications due to the combined benefits of biological nanofibers such as cell attachment and proliferation and that of microfibers such as open structure, larger pore size and adequate mechanical strength. Physico chemical characterization of the electrospun scaffold was done by Scanning Electron Microscopy (SEM), Contact angle analysis, fibrin specific Phosphotungstic acid haematoxyllin (PTAH) staining and evaluation of mechanical properties. SEM data revealed the formation of bead free nanofibers of fibrin with a fiber diameter ranging from 50-500 nm and microfibers of PCL in the size range of 1 microns to 2.5 microns. These dimensions mimic the hierarchical structure of ECM found in native tissues. Cell attachment and viability studies using human mesenchymal stem cells (hMSC) revealed that the scaffold is non toxic and supports cell attachment, spreading and proliferation. In addition, we examined the inflammatory potential of the scaffold to demonstrate its usefulness in tissue engineering applications. Copyright © 2013 American Scientific Publishers All rights reserved.

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2013

T. S. Sonia, Mini, P. A., Nandhini, R., Sujith, K., ,, Subramanian, K. R. V., and Shantikumar V Nair, “Composite Supercapacitor Electrodes Made of Activated Carbon/PEDOT:PSS and Activated Carbon/doped PEDOT”, Bulletin of Materials Science, vol. 36, pp. 547-551, 2013.[Abstract]


In this paper, we report on the high electrical storage capacity of composite electrodes made from nanoscale activated carbon combined with either poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) or PEDOT doped with multiple dopants such as ammonium persulfate (APS) and dimethyl sulfoxide (DMSO). The composites were fabricated by electropolymerization of the conducting polymers (PEDOT:PSS, doped PEDOT) onto the nanoscale activated carbon backbone, wherein the nanoscale activated carbon was produced by ball-milling followed by chemical and thermal treatments. Activated carbon/PEDOT:PSS yielded capacitance values of 640 F g-1 and 26mF cm-2, while activated carbon/doped PEDOT yielded capacitances of 1183 F g-1 and 42 mF cm-2 at 10 mV s-1. This is more than five times the storage capacity previously reported for activated carbon-PEDOT composites. Further, use of multiple dopants in PEDOT improved the storage performance of the composite electrode well over that of PEDOT:PSS. The composite electrodes were characterized for their electrochemical behaviour, structural and morphological details and electronic conductivity and showed promise as high-performance energy storage systems. © Indian Academy of Sciences.

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2013

P. A. Mini, Shantikumar V Nair, and Subramanian, K. R. V., “Design and Development of an Integrated Device Consisting of an Independent Solar Cell with Electrical Storage Capacity”, Progress in Photovoltaics: Research and Applications, vol. 21, pp. 1153-1157, 2013.[Abstract]


A thin film-integrated device was constructed consisting of photovoltaic layers combined with additional layers to store charge in real time within the same device. In our design, a dye-sensitized solar cell and capacitor layers are integrated by a double-anodized titanium plate, which consists of TiO 2 nanotubes grown on either side by electrochemical anodization. The combination device can act either as an independent solar cell, a capacitor, or as a solar cell/capacitor device. The results presented here illustrate the capacitive behavior of high surface area nanotubular metal oxide films, with an achieved capacitance of 140 μF cm-2. Copyright © 2012 John Wiley &amp; Sons, Ltd. This study shows the development of an integrated system, which can simultaneously generate and store electricity from a dye-sensitized solar cell. A capacitor is integrated along with the solar cell; this directly charges upon illumination and discharges whenever required. The present study shows a simple and inexpensive method of developing an integrated system, which could replace an independent solar cell and battery system for generation and storage. Copyright © 2012 John Wiley &amp; Sons, Ltd.

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2013

P. Lekha, Balakrishnan, A., Subramanian, K. R. V., and Shantikumar V Nair, “Size Dependent Electron Transfer from CdTe Quantum Dots Linked to TiO 2 Thin Films in Quantum dot Sensitized Solar Cells”, Materials Chemistry and Physics, vol. 141, pp. 216-222, 2013.[Abstract]


{In this present study, we demonstrate the size dependent charge transfer from CdTe quantum dots (QDs) into TiO2 substrate and relate this charge transfer to the actual behavior of a CdTe sensitized solar cell. CdTe QDs was synthesized using mercaptopropionic acid as the capping agent. The conduction band offset for TiO2 and CdTe QDs indicates thermodynamically favorable band edge positions for smaller QDs for the electron-transfer at the QD-TiO2 interface. Time-resolved emission studies were carried out for CdTe QD on glass and CdTe QD on TiO2 substrates. Results on the quenching of QD luminescence, which relates to the transfer kinetics of electrons from the QD to the TiO2 film, showed that at the smaller QD sizes the transfer kinetics are much more rapid than at the larger sizes. I-V characteristics of quantum dot sensitized solar cells (QDSSC) with different sized QDs were also investigated indicating higher current densities at smaller QD sizes consistent with the charge transfer results. The maximum injection rate constant and photocurrent were obtained for 2.5 nm CdTe QDs. We have been able to construct a solar cell with reasonable characteristics (Voc = 0.8 V

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2013

Anusha Ashokan, Gowd, G. S., Somasundaram, V. H., Bhupathi, A., Peethambaran, R., Unni, A. K. K., ,, Shantikumar V Nair, and Dr. Manzoor K., “Multifunctional Calcium Phosphate Nano-contrast agent for Combined Nuclear, Magnetic and Near-Infrared Invivo Imaging”, Biomaterials, vol. 34, pp. 7143-7157, 2013.[Abstract]


Combination of three imaging techniques such as nuclear, magnetic and near-infrared fluorescence can aid in improved diagnosis of disease by synergizing specific advantages of each of these techniques such as deep tissue penetration of radiation signals, anatomical and functional details provided by magnetic contrast and better spatial resolution of optical signals. In the present work, we report the development of a multimodal contrast agent based on calcium phosphate nanoparticles (nCP), doped with both indocyanine green (ICG) and Gadolinium (Gd3+), and labeled with 99m-Technetium-methylene diphosphonate (99mTc-MDP) for combined optical, magnetic and nuclear imaging. In order to obtain the desired tri-modal contrast properties, the concentrations of ICG, Gd3+ and 99mTc were optimized at  0.15wt%, 3.38at% and  0.002ng/mg of nCP, respectively. The leaching-out of ICG was protected by an additional coating of polyethyleneimine (PEI). Toxicological evaluation of the final construct carried out on healthy human mononuclear cells, red-blood cells and platelets, showed excellent hemocompatibility. Invivo multimodal imaging using mice models revealed the ability to provide near-infrared, magnetic and nuclear contrast simultaneously. The nanoparticles also showed the potential for improved MR based angio-imaging of liver. Retention of intravenously administrated nanoparticles in the liver was reduced with PEGylation and the clearance was observed within 48h without causing any major histological changes in vital organs. Thus, we developed a non-toxic tri-modal nano-contrast agent using calcium phosphate nanoparticles and demonstrated its potential for combined nuclear, magnetic and near-infrared imaging invivo. © 2013 Elsevier Ltd.

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2013

R. Nadesh, Narayanan, D., P.r., S., Vadakumpully, S., Dr. Ullas Mony, Koyakkutty, M., Shantikumar V Nair, and Dr. Deepthy Menon, “Hematotoxicological analysis of surface-modified and -unmodified chitosan nanoparticles”, Journal of Biomedical Materials Research - Part A, vol. 101, pp. 2957-2966, 2013.[Abstract]


The increasing interest in using chitosan nanoparticles for controlled drug delivery is hampered by its blood incompatibility, especially for intravenous applications. This study investigated the effects of processing solvents (acetic acid/lactic acid), dispersing media (acidic medium/saline), and surface modifiers (polyethylene glycol, polyvinyl alcohol, and ethylenediaminetetraacetatic acid) on the hemocompatibility of chitosan. Blood compatibility of chitosan nanoparticles prepared by ionotropic gelation with altered surface chemistry was evaluated by assessing their hemolytic activity, platelet aggregation, coagulation, and cytokine induction. It was observed that nanoparticles prepared in lactic acid and dispersed in saline did not show hemolysis, platelet aggregation, or coagulation, whereas nanoparticles prepared in acetic acid showed strong hemolysis. Surface modifiers were not observed to significantly affect blood compatibility, with the exception of EDTA, which delayed blood clotting times. Thus, chitosan nanoparticles prepared in lactic acid and dispersed in saline may be an ideal nanocarrier for parenteral applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:2957-2966, 2013. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

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2013

D. Narayanan, Gopikrishna, J., J., D., Menon, D., and Shantikumar V Nair, “Proteins and Carbohydrates as Polymeric Nanodrug Delivery Systems: Formulation, Properties, and Toxicological Evaluation”, Advances in Polymer Science, vol. 254, pp. 241-268, 2013.[Abstract]


Enhancing the clinical benefits of pharmaceuticals at reduced doses with negligible side effects has been an ever-challenging goal in drug delivery. This pursuit towards an optimal formulation is hugely supported through the development of nanoparticulate delivery systems, which encapsulate the drug in its active form. Nanocarriers have emerged as successful candidates in pharmaceutics owing to their multifaceted characteristics such as the capability to entrap pharmaceutical ingredients at therapeutic dose, better biodistribution, size-dependent clearance, targetability, and controlled/sustained release of single or multiple payloads at the site of interest. Additionally, the requirement that the chosen carrier be biocompatible and biodegradable necessitates the use of biopolymers in entrapping payloads. Among the biopolymers, a wide variety of natural and synthetic carbohydrates and proteins (including starch, chitosan, chitin, dextran, alginate, albumin, casein, fibrin/fibrinogen, gelatin, collagen, whey protein, etc.) have evolved as useful materials for delivering hydrophobic or hydrophilic drugs through oral, intravenous, mucosal, ocular, or nasal routes. Targeted-controlled release of pharmaceuticals to diseased sites, environmentally stimulated drug release at desired locations, and many more drug release strategies have been made available by efficient engineering and nanoformulation of carbohydrate and protein biopolymers. This chapter embodies an in-depth discussion of various carbohydrate- and protein-based nanomedicines with respect to the formulation and properties of the nanoconstructs. The manipulation and utilization of these properties for development of better drug delivery devices is described and the toxicological interactions of these nanocarriers with host physiological systems discussed. © 2013 Springer-Verlag Berlin Heidelberg.

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2013

T. S. Sonia, Sivakumar, N., Balakrishnan, A., Nair, S., Subramanian, K. R. V., and Shantikumar V Nair, “Thin Film Carbon-sulfur Cathodes by Electrophoretic Deposition for a Prototype Lithium Sulfur Battery System”, Science of Advanced Materials, vol. 5, pp. 1828-1836, 2013.[Abstract]


The present study reports on the fabrication of thin-film nanocomposites of activated carbon-sulfur prepared by electrophoretic deposition onto titanium plates, as cathode materials for a prototype battery. A key aspect of this study is the deposition process, which provides a uniform and fine highly porous microstructure for the cathode. The electrophoretic process is simple, less energy intensive with more control of the C-S ratios and particle sizes than some of the reported methods. The study investigates the performance of this cathode material against a pre-lithiated silicon anode as well as against conventional Li foil anodes. With the conventional Li anodes the results (an energy density of about 690±10 W h kg-1) are comparable to those currently in the literature for full cells. With pre-lithiated Si anodes, the electrophoretic architecture gives improved voltages and improved cycling stability compared to other studies where complex C-S architectures are used, and this appears to be related in part to lower S dissolution in these deposited structures. Overall, the results indicated the strength of the simple electrophoretic process for preparation of the carbon-sulfur cathode material. © 2013 by American Scientific Publishers.

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2013

N. S. Binulal, Natarajan, A., Dr. Deepthy Menon, Bhaskaran, V. K., Dr. Ullas Mony, and Shantikumar V Nair, “PCL-gelatin composite nanofibers electrospun using diluted acetic acid-ethyl acetate solvent system for stem cell-based bone tissue engineering”, Journal of Biomaterials Science, Polymer Edition, vol. 25, no. 4, 2013.[Abstract]


Composite nanofibrous scaffolds with various poly(ε-caprolactone) (PCL)/gelatin ratios (90:10, 80:20, 70:30, 60:40, 50:50 wt.%) were successfully electrospun using diluted acetic and ethyl acetate mixture. The effects of this solvent system on the solution properties of the composites and its electrospinning properties were investigated. Viscosity and conductivity of the solutions, with the addition of gelatin, allowed for the electrospinning of uniform nanofibers with increasing hydrophilicity and degradation. Composite nanofibers containing 30 and 40 wt.% gelatin showed an optimum combination of hydrophilicity and degradability and also maintained the structural integrity of the scaffold. Human mesenchymal stem cells (hMSCs) showed favorable interaction with and proliferation on, the composite scaffolds. hMSC proliferation was highest in the 30 and 40 wt.% gelatin containing composites. Our experimental data suggested that PCL-gelatin composite nanofibers containing 30-40 wt.% of gelatin and electrospun in diluted acetic acid-ethyl acetate mixture produced nanofiber scaffolds with optimum hydrophilicity, degradability, and bio-functionality for stem cell-based bone tissue engineering.

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2013

J. C. Mohan, Praveen, G., Chennazhi, K. P., Jayakumar, R., and Shantikumar V Nair, “Functionalised Gold Nanoparticles for Selective Induction of in Vitro Apoptosis among Human Cancer Cell Lines”, Journal of Experimental Nanoscience, vol. 8, pp. 32-45, 2013.[Abstract]


The interaction of citrate- and polyethylene imine (PEI)-functionalised gold nanoparticles (GNP) with cancer cell lines with respect to the cellular response was studied. It was found that GNP/citrate nanoparticles were able to induce apoptosis in human carcinoma lung cell lines A549, but GNP/PEI did not show any reduction in the viability of the cells in human breast cancer cell line MCF-7 and A549 cell lines. FACS data confirmed that the number of apoptotic cells increased with increase in the concentration of GNP/citrate nanoparticles. Decline in cellular expansion and changes in the nuclear morphology were noted after the treatment of GNP/citrate nanoparticles on A549 cell lines, which itself is a direct response for stress induction. The induction of cellular apoptosis was further confirmed by DNA fragmentation assay. These data confirm the potential of GNP/citrate nanoparticle to evoke cell-specific death response in the A549 cell lines. © 2013 Taylor & Francis.

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2012

S. Mangalathillam, Rejinold, N. S., Nair, A., Lakshmanan, V. - K., Shantikumar V Nair, Dr. Jayakumar Rangasamy, and Dr. Sabitha M., “Curcumin Loaded Chitin Nanogels for Skin Cancer Treatment via the Transdermal Route”, Nanoscale, vol. 4, pp. 239-250, 2012.[Abstract]


In this study, curcumin loaded chitin nanogels (CCNGs) were developed using biocompatible and biodegradable chitin with an anticancer curcumin drug. Chitin, as well as curcumin, is insoluble in water. However, the developed CCNGs form a very good and stable dispersion in water. The CCNGs were analyzed by DLS, SEM and FTIR and showed spherical particles in a size range of 70-80 nm. The CCNGs showed higher release at acidic pH compared to neutral pH. The cytotoxicity of the nanogels were analyzed on human dermal fibroblast cells (HDF) and A375 (human melanoma) cell lines and the results show that CCNGs have specific toxicity on melanoma in a concentration range of 0.1-1.0 mg mL -1, but less toxicity towards HDF cells. The confocal analysis confirmed the uptake of CCNGs by A375. The apoptotic effect of CCNGs was analyzed by a flow-cytometric assay and the results indicate that CCNGs at the higher concentration of the cytotoxic range showed comparable apoptosis as the control curcumin, in which there was negligible apoptosis induced by the control chitin nanogels. The CCNGs showed a 4-fold increase in steady state transdermal flux of curcumin as compared to that of control curcumin solution. The histopathology studies of the porcine skin samples treated with the prepared materials showed loosening of the horny layer of the epidermis, facilitating penetration with no observed signs of inflammation. These results suggest that the formulated CCNGs offer specific advantage for the treatment of melanoma, the most common and serious type of skin cancer, by effective transdermal penetration.

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2012

Anusha Ashokan, Parwathy Chandran, Sadanandan, A. R., Chaitanya K. Koduri, Retnakumari, A. P., Menon, D., Shantikumar V Nair, and Dr. Manzoor K., “Development and Haematotoxicological Evaluation of Doped Hydroxyapatite based Multimodal Nanocontrast Agent for Near-infrared, Magnetic Resonance and X-ray Contrast Imaging”, Nanotoxicology, vol. 6, pp. 652-666, 2012.[Abstract]


Multimodal molecular imaging provides both anatomical and molecular information, aiding early stage detection and better treatment planning of diseased conditions. Here, we report development and nanotoxicity evaluation of a novel hydroxyapatite nanoparticle (nHAp) based multimodal contrast agent for combined near-infrared (NIR), MR and X-ray imaging. Under optimised wet-chemical conditions, we achieved simultaneous doping of nHAp (size ∼50 nm) with indocyanine green and Gd3+ contributing to NIR contrast (∼750–850 nm), paramagnetic behaviour and X-ray absorption suitable for NIR, MR and X-ray contrast imaging, respectively. Haematocompatibility studies using stem cell viability, haemolysis, platelet activation, platelet aggregation and coagulation time analysis indicated excellent compatibility of doped nHAp (D-nHAp). Further, the immunogenic function studies using human lymphocytes (in vitro) showed that D-nHAp caused no adverse effects. Collectively, our studies suggest that D-nHAp with excellent biocompatibility and multifunctional properties is a promising nanocontrast agent for combined NIR, MR and X-ray imaging applications

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2011

N. S. Rejinold, Muthunarayanan, M., Chennazhi, K. P., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “5-Fluorouracil Loaded Fibrinogen Nanoparticles for Cancer Drug Delivery Applications”, International Journal of Biological Macromolecules, vol. 48, pp. 98-105, 2011.[Abstract]


In this study, 5-flurouracil loaded fibrinogen nanoparticles (5-FU-FNPs) were prepared by two step coacervation method using calcium chloride as cross-linker. The prepared nanoparticles were characterized using DLS, SEM, AFM, FT-IR, TG/DTA and XRD studies. Particle size of 5-FU-FNPs was found to be 150-200 nm. The loading efficiency (LE) and in vitro drug release was studied using UV spectrophotometer. The LE of FNPs was found to be ∼90%. The cytotoxicity studies showed 5-FU-FNPs were toxic to MCF7, PC3 and KB cells while they are comparatively non toxic to L929 cells. Cellular uptake of Rhodamine 123 conjugated 5-FU-FNPs was also studied. Cell uptake studies demonstrated that the nanoparticles are inside the cells. These results indicated that FNPs could be useful for cancer drug delivery. © 2010 Elsevier B.V.

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2011

A. Anitha, Deepa, N., Chennazhi, K. P., Shantikumar V Nair, Tamura, H., and Dr. Jayakumar Rangasamy, “Development of Mucoadhesive Thiolated Chitosan Nanoparticles for Biomedical Applications”, Carbohydrate Polymers, vol. 83, pp. 66-73, 2011.[Abstract]


The main objective of this work was to develop nanoparticles (NPs) of a mucoadhesive polymer based on chitosan for biomedical applications. Here, we developed thiolated chitosan (TCS) using thioglycolic acid (TGA) and chitosan in the presence of 1-ethyl-3-3(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) as catalyst. The prepared TCS was characterized using FT-IR and the degree of thiol substitution was found out by Ellman's method. The TCS nanoparticles (TCS-NPs) were developed using ionic cross-linking reaction with pentasodium tripolyphosphate (TPP). The prepared TCS-NPs were characterized by DLS, AFM, FT-IR, TG/DTA, etc. In vitro cytocompatibility and cell uptake studies were also carried out. These studies suggest that the prepared NPs show less toxicity towards normal and cancer cells and they are easily taken up by both the normal and cancer cells. So the prepared TCS-NPs could be used for drug and gene delivery applications. © 2010 Elsevier Ltd.

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2011

A. Anitha, Maya, S., Deepa, N., Chennazhi, K. P., Shantikumar V Nair, Tamura, H., and Dr. Jayakumar Rangasamy, “Efficient Water Soluble O-carboxymethyl Chitosan Nanocarrier for the Delivery of Curcumin to Cancer Cells”, Carbohydrate Polymers, vol. 83, pp. 452-461, 2011.[Abstract]


Carboxymethyl chitosan derivatives are widely used for biomedical applications because of their non-toxic and biodegradable properties. Curcumin is a phytochemical with immense biological properties. But its hydrophobicity and poor oral bioavailability limits its application as a chemotherapeutic agent. To increase the oral bioavailability, we developed curcumin loaded O-CMC nanoparticles (curcumin-O-CMC Nps). The prepared nanoparticles were characterized by DLS, AFM, SEM, FT-IR, XRD and TG/DTA. Size analysis studies revealed spherical particles with mean diameter of about 150 ± 30 nm. Curcumin was entrapped in O-CMC with an efficiency of 87%. In vitro drug release profile was studied at 37 °C under different pHs (7.4 and 4.5) with and without lysozyme. Cytotoxicity studies by MTT assay indicated that curcumin-O-CMC Nps were toxic to cancer and non-toxic to normal cells. Cellular uptake of the curcumin-O-CMC Nps was analyzed by fluorescence microscopy and FACS. Overall these studies indicated O-CMC as a promising nanomatrix for drug delivery applications. © 2010 Elsevier Ltd. All rights reserved.

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2011

S. N. Rejinold, Chennazhi, K. P., Shantikumar V Nair, Tamura, H., and Dr. Jayakumar Rangasamy, “Biodegradable and Thermo-Sensitive Chitosan-g-poly(N-vinylcaprolactam) Nanoparticles as a 5-fluorouracil Carrier”, Carbohydrate Polymers, vol. 83, pp. 776 - 786, 2011.[Abstract]


We developed a nanoformulation of 5-FU (5-fluorouracil) with biodegradable thermo-responsive chitosan-g-poly(N-vinylcaprolactam) biopolymer composite for its delivery to cancer cells. The novel thermo-responsive graft co-polymeric nanoparticles (TRC-NPs) were prepared by ionic cross-linking method, which showed a lower critical solution temperature (LCST) at 38°C. The 5-FU drug was incorporated into the carrier using cross-linking reaction. The in vitro drug release showed prominent release above LCST. Cytotoxicity assay showed TRC-NPs in the concentration range of 100–1000μg/ml are non-toxic to an array of cell lines. The drug-loaded nanoparticles showed comparatively higher toxicity to cancer cells while they are less toxic to normal cells. The cell uptake of the 5-FU loaded thermo-responsive graft co-polymeric nanoparticles (5-FU–TRC-NPs) was confirmed from green fluorescence inside cells by rhodamine-123 conjugation. The apoptosis assay showed increased apoptosis of cancer cells when treated with 5-FU compared to the normal cells. These results indicated that novel 5-FU–TRC-NPs could be a promising candidate for cancer drug delivery.

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2011

K. T. Shalumon, Binulal, N. S., Deepthy, M., Dr. Jayakumar Rangasamy, Koyakutty, M., and Shantikumar V Nair, “Preparation, Characterization and Cell Attachment Studies of Electrospun Multi-scale Poly(caprolactone) Fibrous Scaffolds for Tissue Engineering”, Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, vol. 48, pp. 21-30, 2011.[Abstract]


Electrospun nano, micro and micro/nano (multiscale) poly(caprolactone) (PCL) fibrous scaffolds with and without nano hydroxyapatite (nHAp) was prepared. All the scaffolds were evaluated for its spectroscopic, morphological, mechanical, thermal, cell attachment and protein adsorption properties. The cell attachment studies showed that cell activity on the nano-fibrous, as well as multi-scale scaffolds with and without nHAp was higher compared to micro-fibrous scaffolds. A time dependent cell attachment study on aligned micro-fibers was carried out to elucidate the difference in cell interaction on micro-fibers. The cell activity, proliferation and total protein adsorption on the nano-fibers/nano-fibers with nHAp was significantly higher than on the micro-fibers, although the adsorption per unit area was less on the nano-fibers due to the much higher surface area of nano-fibers. These results suggest that a combination of a micro- and nano-fiber hierarchical scaffold could be more beneficial for tissue engineering applications than the individual scaffolds provided the amount of nano- fibers could be suitably optimized. Copyright © Taylor &amp; Francis Group, LLC.

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2011

V. V. D. Rani, Ramachandran, R., Chennazhi, K. P., Tamura, H., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Fabrication of Alginate/NanoTiO2 Needle Composite Scaffolds for Tissue Engineering Applications”, Carbohydrate Polymers, vol. 83, pp. 858-864, 2011.[Abstract]


Alginate is a naturally occurring polymer that has been widely accepted as biodegradable and biocompatible material. Incorporation of nanoceramic will improve the capability of polymeric scaffold for tissue regeneration. Hence, in this study we fabricated a nanocomposite scaffold using alginate with nanoTiO2 needles by lyophilization technique. The prepared nanocomposite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the scaffold were also evaluated. The developed nanocomposite scaffolds showed well controlled swelling and degradation when compared to the control alginate scaffold. Cytocompatibility was assessed using MTT assay and cell attachment studies. Results indicated no sign of toxicity and cells were found to be attached to the pore walls offered by the scaffolds. These results suggested that the developed nanocomposite scaffold possess the prerequisites for tissue engineering application. Hence, alginate/nanoTiO2 composite scaffold can be used as a better option for tissue regeneration. © 2010 Elsevier Ltd. All rights reserved.

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2011

Dr. Jayakumar Rangasamy, Ramachandran, R., Divyarani, V. V., Chennazhi, K. P., Tamura, H., and Shantikumar V Nair, “Fabrication of Chitin-chitosan/nano TiO2-Composite Scaffolds for Tissue Engineering Applications”, International Journal of Biological Macromolecules, vol. 48, pp. 336-344, 2011.[Abstract]


In this study, we prepared chitin-chitosan/nano TiO2 composite scaffolds using lyophilization technique for bone tissue engineering. The prepared composite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the composite scaffolds were evaluated. The developed composite scaffold showed controlled swelling and degradation when compared to the control scaffold. Cytocompatibility of the scaffold was assessed by MTT assay and cell attachment studies using osteoblast-like cells (MG-63), fibroblast cells (L929) and human mesenchymal stem cells (hMSCs). Results indicated no sign of toxicity and cells were found attached to the pore walls within the scaffolds. These results suggested that the developed composite scaffold possess the prerequisites for tissue engineering scaffolds and it can be used for tissue engineering applications. © 2010 Elsevier B.V.

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2011

Dr. Jayakumar Rangasamy, Chennazhi, K. P., Srinivasan, S., Shantikumar V Nair, Furuike, T., and Tamura, H., “Chitin Scaffolds in Tissue Engineering”, International Journal of Molecular Sciences, vol. 12, pp. 1876-1887, 2011.[Abstract]


Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

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2011

A. Jayasree, Sasidharan, S., Koyakutty, M., Shantikumar V Nair, and Menon, D., “Mannosylated Chitosan-zinc Sulphide Nanocrystals as Fluorescent Bioprobes for Targeted Cancer Imaging”, Carbohydrate Polymers, vol. 85, pp. 37-43, 2011.[Abstract]


A novel nanomaterial based on chitosan-zinc sulphide:Mn (ZnS:Mn) conjugated with mannose ligand has been developed for targeted cancer imaging. The nanobioconjugates, prepared through simple aqueous chemistry, possessed high colloidal stability and strong fluorescence emission at ∼600 nm. Characterization using XRD, DLS, SEM, AFM and FTIR revealed that the bioconjugated particles are appropriately functionalized and stable, with average size ∼150 nm. The presence of polysaccharide chitosan bestowed enhanced biocompatibility to the nanocrystals and provided suitable functionality for mannosylation. In vitro cytotoxicity studies on mouse fibroblast (L929) and oral epithelial carcinoma (KB) cells confirmed their cytocompatibility. Bioconjugation with mannose provided specificity and targeted cellular labelling characteristics as demonstrated using KB cells which over-express mannose receptors on their surface. Our investigations highlight the applicability of polysaccharide protected and mannosylated fluorescent ZnS nanoprobes for active targeting of cancer cells. © 2011 Elsevier Ltd. All rights reserved.

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2011

P. A. Mini, Balakrishnan, A., Shantikumar V Nair, and Subramanian, K. R. V., “Highly Super Capacitive Electrodes made of Graphene/poly(pyrrole)”, Chemical Communications, vol. 47, pp. 5753-5755, 2011.[Abstract]


We report on the development and characterization of high performance supercapacitor electrodes synthesized using electrophoretic deposition of graphene, upon which the poly(pyrrole)-layer was electropolymerised. The highly capacitive electrode had a specific capacitance of 1510 F g-1, area capacitance of 151 mF cm-2 and volume capacitance of 151 F cm -3 at 10 mV s-1. © 2011 The Royal Society of Chemistry.

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2011

S. N. Rejinold, Sreerekha, P. R., Chennazhi, K. P., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Biocompatible, Biodegradable and Thermo-Sensitive Chitosan-g-poly (N-isopropylacrylamide) Nanocarrier for Curcumin Drug Delivery”, International Journal of Biological Macromolecules, vol. 49, pp. 161-172, 2011.[Abstract]


A nano formulation of curcumin loaded biodegradable thermoresponsive chitosan-g-poly (N-isopropylacrylamide) co-polymeric nanoparticles (TRC-NPs) (150. nm) were prepared by ionic cross-linking method and characterized. The in vitro drug release was prominent at above LCST. Cytocompatibility of TRC-NPs (100-1000 μg/ml) on an array of cell line is proved by MTT assay. The drug loaded TRC-NPs showed specific toxicity on cancer cells. The cell uptake studies were confirmed by fluorescent microscopy. Flowcytometric analysis of curcumin loaded TRC-NPs showed increased apoptosis on PC3 cells. These results indicated that TRC-NPs could be a potential nanovehicle for curcumin drug delivery. © 2011 Elsevier B.V.

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2011

S. N. Rejinold, Muthunarayanan, M., Chennazhi, K. P., Shantikumar V Nair, and Dr. Jayakumar Rangasamy, “Curcumin Loaded Fibrinogen Nanoparticles for Cancer Drug Delivery”, Journal of Biomedical Nanotechnology, vol. 7, pp. 521-534, 2011.[Abstract]


In this work we prepared and evaluated the curcumin loaded fibrinogen nanoparticles (CRC-FNPs) as a novel drug delivery system for cancer therapy. These novel CRC-FNPs were prepared by a two-step co-acervation method using calcium chloride as the cross-linker. The prepared nanoparticles were characterized using dynamic light scattering (DLS), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TG), differential thermal analysis (DTA) and X-ray diffraction (XRD) studies. DLS studies showed that the particle size of CRC-FNPs was in the range of 150-200 nm. The loading efficiency (LE) and in vitro drug release were studied using UV spectrophotometer. The LE was found to be 90%. The cytotoxicity was studied using L929 (mouse fibroblast), PC3 (prostate) and MCF7 (breast) cancer cell lines by MTT assay, which confirmed that CRC-FNPs were comparatively non toxic to L929 cell line while toxic to PC3 and MCF7 cancer cells. Cellular uptake of CRC-FNPs studied using L929, MCF-7 and PC3 cells monitored by fluorescent microscopy, demonstrated significant internalization and retention of nanoparticles inside the cells. The preferential accumulation of curcumin within the cancer cells were also confirmed by flowcytometry based uptake studies. The apoptosis assay showed increased apoptosis on MCF-7 compared to L929 cells. The blood compatibility of CRC-FNPs throws light on the fact that it is possible to administer the prepared nanoformulation intravenously. The results indicated that CRC-FNPs could be a promising therapeutic agent for cancer treatment. Copyright © 2011 American Scientific Publishers All rights reserved.

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2011

P. Chandran, Abhilash Sasidharan, Anusha Ashokan, Menon, D., Shantikumar V Nair, and Dr. Manzoor K., “Highly Biocompatible TiO2:Gd3+ Nano-contrast Agent with Enhanced Longitudinal Relaxivity for Targeted Cancer Imaging”, Nanoscale, vol. 3, pp. 4150-4161, 2011.[Abstract]


We report the development of a novel magnetic nano-contrast agent (nano-CA) based on Gd3+ doped amorphous TiO2 of size ∼25 nm, exhibiting enhanced longitudinal relaxivity (r1) and magnetic resonance (MR) contrasting together with excellent biocompatibility. Quantitative T1 mapping of phantom samples using a 1.5 T clinical MR imaging system revealed that the amorphous phase of doped titania has the highest r 1 relaxivity which is ∼2.5 fold higher than the commercially used CA Magnevist™. The crystalline (anatase) samples formed by air annealing at 250 °C and 500 °C showed significant reduction in r1 values and MR contrast, which is attributed to the loss of proton-exchange contribution from the adsorbed water and atomic re-arrangement of Gd 3+ ions in the crystalline host lattice. Nanotoxicity studies including cell viability, plasma membrane integrity, reactive oxygen stress and expression of pro-inflammatory cytokines, performed on human primary endothelial cells (HUVEC), human blood derived peripheral blood mononuclear cells (PBMC) and nasopharyngeal epidermoid carcinoma (KB) cell line showed excellent biocompatibility up to relatively higher doses of 200 μg ml-1. The potential of this nano-CA to cause hemolysis, platelet aggregation and plasma coagulation were studied using human peripheral blood samples and found no adverse effects, illustrating the possibility of the safe intravenous administration of these agents for human applications. Furthermore, the ability of these agents to specifically detect cancer cells by targeting molecular receptors on the cell membrane was demonstrated on folate receptor (FR) positive oral carcinoma (KB) cells, where the folic acid conjugated nano-CA showed receptor specific accumulation on cell membrane while leaving the normal fibroblast cells (L929) unstained. This study reveals that the Gd3+ doped amorphous TiO2 nanoparticles having enhanced magnetic resonance contrast and high biocompatibility is a promising candidate for molecular receptor targeted MR imaging. © 2011 The Royal Society of Chemistry.

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2011

K. T. Shalumon, Anulekha, K. H., Shantikumar V Nair, Chennazhi, K. P., and Dr. Jayakumar Rangasamy, “Sodium Alginate/poly(vinyl alcohol)/nano ZnO Composite Nanofibers for Antibacterial Wound Dressings”, International Journal of Biological Macromolecules, vol. 49, pp. 247-254, 2011.[Abstract]


Sodium alginate (SA)/poly (vinyl alcohol) (PVA) fibrous mats were prepared by electrospinning technique. ZnO nanoparticles of size &nbsp;160. nm was synthesized and characterized by UV spectroscopy, dynamic light scattering (DLS), XRD and infrared spectroscopy (IR). SA/PVA electrospinning was further carried out with ZnO with different concentrations (0.5, 1, 2 and 5%) to get SA/PVA/ZnO composite nanofibers. The prepared composite nanofibers were characterized using FT-IR, XRD, TGA and SEM studies. Cytotoxicity studies performed to examine the cytocompatibility of bare and composite SA/PVA fibers indicate that those with 0.5 and 1% ZnO concentrations are less toxic where as those with higher concentrations of ZnO is toxic in nature. Cell adhesion potential of this mats were further proved by studying with L929 cells for different time intervals. Antibacterial activity of SA/PVA/ZnO mats were examined with two different bacteria strains; Staphylococcus aureus and Escherichia coli, and found that SA/PVA/ZnO mats shows antibacterial activity due to the presence of ZnO. Our results suggest that this could be an ideal biomaterial for wound dressing applications once the optimal concentration of ZnO which will give least toxicity while providing maximum antibacterial activity is identified.f. © 2011 Elsevier B.V.

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2011

S. R. Perumcherry, Chennazhi, K. P., Shantikumar V Nair, Menon, D., and Afeesh, R., “A Novel Method for the Fabrication of Fibrin-based Electrospun Nanofibrous Scaffold for Tissue-Engineering Applications”, Tissue Engineering - Part C: Methods, vol. 17, pp. 1121-1130, 2011.[Abstract]


In this study, fibrin, which is superior to fibrinogen in both structural and functional properties, has for the first time been electrospun successfully into uniform nano fibers resembling the extracellular matrix (ECM). The methods of fabrication and characterization of this unique scaffold are presented. Using poly (vinyl) alcohol as an electrospinning-driving polymer, we have developed a novel method for the fabrication of fibrin into a nanofibrous scaffold for various tissue-engineering applications starting from human-plasma-derived fibrinogen and thrombin and combining these ingredients within the syringe of an electrospinning setup under high voltage. In this fashion, fibrin nanofibrous scaffold is produced in a one-step approach without the need for subsequent cross-linking by synthetic agents that compromise the biological properties of the scaffold. Characterization of the electrospun membrane was done by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and fibrin specific phosphotungstic acid hematoxylin staining. SEM data revealed the formation of bead-free fibers with a dimension ranging from 50-500nm, which exactly mimics the fiber diameter of native ECM. Cell attachment and proliferation studies revealed that the scaffold supports the attachment, spreading, and proliferation of human umbilical cord blood-derived mesenchymal stem cells. © 2011, Mary Ann Liebert, Inc.

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2010

J. R, K.P, C., Shantikumar V Nair, T., F., and H., T., “Chitosan-Conjugated DNA Nanoparticle Delivery Systems for Gene Therapy”, Chitin, Chitosan, Oligosaccharides and Their Derivatives: Biological Activities and Applications, 2010.

2010

N. S. Binulal, Deepthy, M., Selvamurugan, N., Shalumon, K. T., Suja, S., Dr. Ullas Mony, Dr. Jayakumar Rangasamy, and Shantikumar V Nair, “Role of Nanofibrous Poly(caprolactone) Scaffolds in Human Mesenchymal Stem Cell Attachment and Spreading for in Vitro Bone Tissue Engineering-response to Osteogenic Regulators”, Tissue Engineering - Part A, vol. 16, pp. 393-404, 2010.[Abstract]


In this study, we evaluated the role of fiber size scale in the adhesion and spreading potential of human mesenchymal stem cells (hMSCs) on electrospun poly(caprolactone) (PCL) nanofibrous and microfibrous scaffolds. The effect of in vivo regulators in inducing osteogenic differentiation of hMSCs on PCL nanofibrous scaffolds was investigated using osteogenic differentiation marker gene expression and matrix mineralization. Here, we report for the first time the influence of in vivo regulators in an in vitro setting with hMSCs for bone tissue engineering on PCL nanofibrous matrices. Our results indicated that hMSCs attached and spread rapidly on nanofibrous scaffolds in comparison to microfibrous PCL. Further, hMSCs proliferated well on the nanofibrous scaffolds. The cells on the nanofibrous PCL were found to differentiate into the osteoblast lineage and subsequently mineralize upon addition of in vivo osteogenic regulators. The attachment and spreading of hMSCs were more effective on the nanofibers compared with the microfibers despite the lower protein surface coverage (total adsorbed protein per unit fiber surface area) on nanofibers. Copyright 2010, Mary Ann Liebert, Inc.

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2009

A. Anitha, Rani, V. V. Divya, Krishna, R., Sreeja, V., Selvamurugan, N., Shantikumar V Nair, Tamura, H., and Dr. Jayakumar Rangasamy, “Synthesis, Characterization, Cytotoxicity and Antibacterial Studies of Chitosan, O-carboxymethyl and N,O-carboxymethyl Chitosan Nanoparticles”, Carbohydrate Polymers, vol. 78, pp. 672 - 677, 2009.[Abstract]


Chitosan (CS) is a naturally occurring biopolymer. It has important biological properties such as biocompatibility, antifungal and antibacterial activity, wound healing ability, anticancerous property, anticholesteremic properties, and immunoenhancing effect. Recently, CS nanoparticles have been used for biomedical applications. However, due to the limited solubility of CS in water its water-soluble derivatives are preferred for the above said applications. In this work, the nanoparticles of CS and its water-soluble derivatives such as O-carboxymethyl chitosan (O-CMC) and N,O-carboxymethyl chitosan (N,O-CMC) was synthesized and characterized. In addition, cytotoxicity and antibacterial activity of the prepared nanoparticles was also evaluated for biomedical applications.

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2009

Dr. Jayakumar Rangasamy, H, N., V, D. Rani. V., T, S. K., Shantikumar V Nair, ,, T, F., and , “Preparation and Characterization of α-Chitin/Gelatin Composite Membranes for Tissue Engineering Applications”, International Journal of Biological Macromolecules, vol. 44, no. 4, pp. 333-337, 2009.

2009

K. Manzoor, Johny, S., Thomas, D., Setua, S., Menon, D., and Shantikumar V Nair, “Bio-conjugated Luminescent Quantum Dots of Doped ZnS: A Cyto-friendly System for Targeted Cancer Imaging”, Nanotechnology, vol. 20, 2009.[Abstract]


A heavy-metal-free luminescent quantum dot (QD) based on doped zinc sulfide (ZnS), conjugated with a cancer-targeting ligand, folic acid (FA), is presented as a promising bio-friendly system for targeted cancer imaging. Doped QDs were prepared by a simple aqueous method at room temperature. X-ray diffraction and transmission electron microscopy studies showed the formation of monodisperse QDs of average size ∼4nm with cubic (sphalerite) crystal structure. Doping of the QDs with metals (Al3+), transition metals (Cu+, Mn2+) and halides (F-) resulted in multi-color emission with dopant-specific color tunability ranging from blue (480nm) to red (622nm). Luminescent centers in doped QDs could be excited using bio-friendly visible light &gt;400nm by directly populating the dopant centers, leading to bright emission. The cytotoxicity of bare and FA conjugated QDs was tested invitro using normal lung fibroblast cell line (L929), folate-receptor-positive (FR+) nasopharyngeal epidermoid carcinoma cell line (KB), and FR-negative (FR-) lung cancer cell line (A549). Both bare and FA-conjugated ZnS QDs elicited no apparent toxicity even at high concentrations of ∼100νM and 48h of incubation. In contrast, CdS QDs prepared under identical conditions showed relatively high toxicity even at low concentrations of ∼0.1νM and 24h of incubation. Interaction of FA-QDs with different cell lines showed highly specific attachment of QDs in the FR+ cancer cell line, leaving others unaffected. The bright and stable luminescence of the QDs could be used to image both single cancer cells and colonies of cancer cells without affecting their metabolic activity and morphology. Thus, this study presents, for the first time, the use of non-toxic, Cd-, Te-, Se-, Pb-and Hg-free luminescent QDs for targeted cancer imaging.

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2009

V. V. Divya Rani, Manzoor, K., Menon, D., Selvamurugan, N., and Shantikumar V Nair, “The design of novel nanostructures on titanium by solution chemistry for an improved osteoblast response.”, Nanotechnology, vol. 20, p. 195101, 2009.[Abstract]


We report an interesting cell response to novel nanostructures formed on a titanium (Ti) surface by a simple non-lithographic bottom-up method. The surface topography of bio-implant materials dramatically influences their cell response. The aim of this study was to modify the surface of a titanium implant by a simple and cost effective processing technique and to determine its suitability for osteoblast attachment. A set of unique structures ranging from mesoporous nanoscaffolds, nanoflowers, nanoneedles, nanorods and octahedral bipyramids were fabricated by systematically tuning the hydrothermal conditions such as reaction medium composition, concentration, temperature and time duration. The cytotoxicity of surface modified Ti was assessed using human primary osteoblastic cells, and more than 90% of the cells were found to be viable after 24 h of incubation. Protein adsorption studies revealed that the surface modified nanostructures on titanium adsorbed more proteins, suggesting that they are capable of promoting cell adhesion/attachment. Immunofluorescence studies with vinculin antibody identified a distinctly different spread pattern of osteoblastic cells on hydrothermally modified nanostructured surfaces, indicating the formation of the focal adhesion points required for intracellular signaling. Thus, based on our results, we suggest that this study may present one of the best designs and systematic syntheses of biocompatible nanostructures on metallic Ti for orthopedic implant applications.

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2009

S. Kwok, Partridge, N. C., Srinivasan, N., Shantikumar V Nair, and Selvamurugan, N., “Mitogen Activated Protein Kinase-Dependent Inhibition of Osteocalcin Gene Expression by Transforming Growth Factor-β1”, Journal of Cellular Biochemistry, vol. 106, pp. 161-169, 2009.[Abstract]


TGF-β (transforming growth factor-beta) plays a key role in osteoblast differentiation and bone development. While the ability of TGF-β to inhibit the expression of osteoblast differentiation genes has been well documented, the mechanism of this inhibition is not yet completely characterized. Runx2, a transcription factor necessary for expression of osteoblast differentiation genes is a central target of inhibition by TGF-β. In this study, we found that TGF-β1 inhibits expression of osteoblast differentiation genes without altering expression of Runx2. Transient transfection experiments determined that TGF-β1 inhibited osteocalcin promoter activity and this effect is mediated through Runx2. We further identified that there was no change in protein expression, cellular localization, or DNA binding affinity of Runx2 after TGF-β1-treatment of osteoblasts, suggesting that Runx2 undergoes post-translational modifications following TGF-β1 treatment. Coimmunoprecipitation experiments identified increased phosphorylation of Runx2 when differentiating osteoblasts were treated with TGF-β1. Mitogen activated protein kinase (MAPK) inhibitors relieved the TGF-β1-inhibitory effect of Runx2-mediated osteocalcin expression. Thus, our results suggest that TGF-β1-inhibition of osteoblast differentiation is dependent on the MAPK pathway and this effect is most likely mediated by post-translational modification of Runx2 such as phosphorylation rather than other regulatory mechanisms. J. Cell. Biochem. 106: 161-169, 2009. copy; 2008 Wiley-Liss, Inc.

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2008

U. S. Sajeev, Anand, K. A., Menon, D., and Shantikumar V Nair, “Control of Nanostructures in PVA, PVA/chitosan Blends and PCL through Electrospinning”, Bulletin of Materials Science, vol. 31, pp. 343-351, 2008.[Abstract]


Aqueous solutions of polyvinyl alcohol (PVA) were electrospun and its characteristics were studied as a function of applied potential, tip-target distance and solution flow rate. Solutions of PVA and chitosan were homogeneously mixed and electrospun to result in blend nanofibres and their properties were investigated. Conditions were revealed under which multiscale bi-modal fibres could be electrospun in a single step, producing structures that have potential applications in tissue engineering. Electrospun fibres having a bimodal size distribution of poly(caprolactone) (PCL) were also fabricated using a modified electrospinning setup. Nanofibrous microporous PVA scaffolds were fabricated using a cryogenic grinding method with subsequent compaction. Such multiscale porous structures would offer ideal matrices for tissue engineering applications. © Indian Academy of Sciences.

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Publication Type: Patent

Year of Publication Title

2018

Dr. Deepthy Menon, Joseph, J., and Shantikumar V Nair, “Electrospinning Apparatus and Method for Producing Multi-Dimensional Structures and Core-Sheath Yarns”, 2018.

2018

Dr. Manzoor K., Malarvizhi, G. Loghanatha, and Shantikumar V Nair, “Nanoparticle Formulations for Delivering Multiple Therapeutic Agents”, 2018.[Abstract]


A formulation for treating a patient with hepatocellular carcinoma is disclosed. The formulation comprises therapeutic agents in the form of nanoparticles containing one or more proteins or polysaccharides. The therapeutic agent is conjugated to an active targeting agent causing the formulation to preferentially segregate to the hepatocellular carcinoma tissue to release the therapeutic agents. Methods of treating hepatocellular carcinoma using the formulations are also disclosed.

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2017

, Bernard, C. C. A., Krishnakumar N. Menon, Sadanandan, P., Payne, N. L., and Shantikumar V Nair, “Compositions and Methods for Autoimmune Disease Treatment Inventors”, U.S. Patent Australian Provisional Patent Application no: 2016903294 (Patent Filed)2017.

2017

Anusha Ashokan, Dr. Manzoor K., Shantikumar V Nair, M, S., and Harish, V., “MRI and CT Contrast-enabled Composite Implants for Image-guided Tissue Regeneration and Therapy (Filed)”, U.S. Patent PCT/US2017/0207932017.

2017

Anusha Ashokan, Dr. Manzoor K., Shantikumar V Nair, and Harish, V., “Non-Iodinated Radiolabeled Radiopaque Microbeads with MRI Contrast for Radioembolization (Filed)”, U.S. Patent PCT/US2017/0334862017.

2017

Shantikumar V Nair, Dr. Manzoor K., and P, A., “Core - shell particle formulation for delivering multiple therapeutic agents”, 2017.

2017

Dr. Manzoor K., Malarvizhi, G. Loghanatha, and Shantikumar V Nair, “Nanoparticle formulations for delivering multiple therapeutic agents ”, 2017.[Abstract]


A formulation for treating a patient with hepatocellular carcinoma is disclosed. The formulation comprises therapeutic agents in the form of nanoparticles containing one or more proteins or polysaccharides. The therapeutic agent is conjugated to an active targeting agent causing the formulation to preferentially segregate to the hepatocellular carcinoma tissue to release the therapeutic agents. Methods of treating hepatocellular carcinoma using the formulations are also disclosed.

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2017

Dr. Manzoor K., Malarvizhi, G. Loghanatha, and Shantikumar V Nair, “Cartridge Connection Method for Precise Delivery of Liquid”, 2017.[Abstract]


A formulation for treating a patient with hepatocellular carcinoma is disclosed. The formulation comprises therapeutic agents in the form of nanoparticles containing one or more proteins or polysaccharides. The therapeutic agent is conjugated to an active targeting agent causing the formulation to preferentially segregate to the hepatocellular carcinoma tissue to release the therapeutic agents. Methods of treating hepatocellular carcinoma using the formulations are also disclosed.

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2016

Shantikumar V Nair, Dr. Manzoor K., and P, A., “Core-shell particle formulation for delivering multiple therapeutic”, 2016.

2015

Dr. Manzoor K., Robinson, D. J., Sterenborg, H. J. C. M., Kascakova, S., and Shantikumar V Nair, “Targeted Nano-photomedicines for Photodynamic Therapy of Cancer (Chinese)”, 2015.[Abstract]


The present invention relates to nanoparticles containing a photosensitizer, said nanoparticles comprising: one photosensitizer, the photosensitizer through at least a portion of the nanoparticle is covalently bonded to the nanoparticle matrix material and state of aggregation and quasi- into the nanoparticle matrix. The present invention further relates to a process for preparing nanoparticles of the present invention, and the use of the nanoparticles photodynamic therapy method of killing cancer cells.

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2015

Dr. Manzoor K., Anusha Ashokan, Harish, V., and Shantikumar V Nair, “Radio-Wave Responsive Doped Nanoparticles for Image Guided Therapeutics (Filed)”, U.S. Patent 6495/CHE/20152015.

2014

Dr. Manzoor K., Ashokan, A., Dr. Deepthy Menon, and Shantikumar V Nair, “The art, method, manner, process and system of multifunctional nanobiomaterial for molecular imaging and drug- delivery”, U.S. Patent PCT/IN2013/0001422014.[Abstract]


The present invention relates to a nano-sized material that can provide contrast enhancement for multiple molecular imaging mthods and also deliver therapeutic nucleic acids or chemodrugs at a specific site of disease such as cancer. In particular, the present invention relates to a nanosized synthetic calcium apatite based materials showing contrast imaging for visible to near-infrared fluroscence, magnetic resonance imaging and x-ray imaging together with targeted delivery of nucleic acid drugs (DNA or RNA) to specific cancer types.

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2014

Dr. Manzoor K., Ashokan, A., and Shantikumar V Nair, “The art, method, manner, process and system of a nano-biomineral for multi-modal contrast imaging and drug delivery”, U.S. Patent PCT/IN2013/0001432014.[Abstract]


The present invention relates to a nano-sized material that can provide contrast enhancement for multple imaging methods and also deliver therapeutic molecules such as nucleic acids or chemo drugs to diseased sites such as cancer. In particular, the present invention relates to nano-sized synthetic calcium phosphates and calcium apatite nanomaterials showing simultaneous contrast for at least any two of the medical imaging modalities including radio, raman-, near-infrared fluroscence-, magnetic resonance and x-ray-imaging.

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2014

Dr. Manzoor K., Retnakumari, A., and Shantikumar V Nair, “A core-shell nanostructure on the basis of proteins with corresponding therapeutic agents”, U.S. Patent PCT/IN2013/0001412014.[Abstract]


The present invention is related to the design and synthesis of nanomedicine comprising of a protein-protein composite or core-shell nanoparticle, where one protein carries one type of therapeutic molecule and second protein carries another type of therapeutic molecule. This nanomedicine formulation is intended for the treatment of diseases including cancer. To be specific, the current invention is designed to deliver two different types of therapeutic molecules in sequence or in combination using a single entity of nanoparticle formed by two different proteins that carry two therapeutic molecules separately

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2013

V. Harish, K, M., and Shantikumar V Nair, “THE ART, METHOD, MANNER, PROCESS AND SYSTEM OF STANNOUS DOPED MICRO AND NANO CONSTRUCTS FOR AUGMENTED RADIOFREQUENCY ABLATION”, U.S. Patent 156/CHE/2013 (AMRT-0044IN)2013.

2013

Dr. Manzoor K., PARWATHY, C., Archana, P. R., and Shantikumar V Nair, “Polymer - polymer or polymer - protein core - shell nano medicine loaded with multiple drug molecules”, U.S. Patent PCT/IN2013/0001082013.[Abstract]


The present invention relates to the method of synthesis of core-shell nano medicine serving as a novel platform for the encapsulation of multiple therapeutic molecules enabling combinatorial therapy against diseases including cancer, inflammatory and auto-immune diseases and its associated manifestations. The core-shell nano-construct comprises of a biodegradable and biocompatible polymer as the core and another polymer or protein as the shell, aiding following constructs (i) polymer core-polymer shell and (ii) polymer core-protein shell. The core-shell nano medicine is developed in a manner to encapsulate at least one anti-cancer agent each in both the core and the shell

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2013

R. Ramachandran, Dr. Manzoor K., and Shantikumar V Nair, “The art, method,manner process and system of fibrous bio-degradable polymeric wafers for the local delivery of therapeutic agents in combinations”, U.S. Patent PCT/IN2013/0001102013.[Abstract]


The present invention is related to flexible, fibrous, biocompatible and biodegradable polymeric wafer consisting of more than one polymeric fibres, each one loaded with different therapeutic agents having mutually exclusive synergistic activity. The wafer is capable of delivering the drugs locally in to the deceased site like tumor, inflammation, wound etc in a controlled and sustained fashion for enhanced therapeutic effect. The combination of drugs loaded in the wafer is chosen in such a way that the second or consecutive drugs will enhance or improve the therapeutic effect of the first drug

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2012

K. R. V. Subramanian, Shantikumar V Nair, Lal, M., AVINASH BALAKRISHNAN, and Sivakumar, N., “The method, Manner, Process and System of Preparation of Super capacitor or Battery Anodes using novel activated Carbon Graphene or Activated Carbon-Graphite Composites by Electrophoretic Co-deposition”, U.S. Patent 3428/CHE/20122012.

2012

Dr. Manzoor K., Shantikumar V Nair, Dr. Deepthy Menon, and Asok, A., “THE ART, METHOD, MANNER, PROCESS AND SYSTEM OF MULTIFUNCTIONAL NANOMEDICINE FOR MOLECULAR IMAGING AND SCINTILLATION THERAPY”, U.S. Patent 26/CHE/20122012.

2012

Dr. Manzoor K., Anusha Ashokan, and Shantikumar V Nair, “THE ART, METHOD, MANNER, PROCESS AND SYSTEM OF NANO-BIOMINERAL FOR MULTIMODAL CONTRAST IMGING AND DRUG DELIVERY (Filed)”, U.S. Patent 25/CHE/20122012.

2012

M. Koyakutty, Robinson, D. J., Sterenborg, H. J. C. M., Kascakova, S., and Shantikumar V Nair, “Targeted nano-photomedicines for photodynamic therapy of cancer”, U.S. Patent EP200907881932012.[Abstract]


The present invention relates to a photosensitizer-containing nanoparticle, comprising a photosensitizer covalently bonded throughout at least a part of said nanoparticle to the nanoparticle matrix material and incorporated therein in a quasi-aggregated state. The present invention further relates to methods for producing the invention nanoparticles, and to methods of killing cancer cells by PDT treatment using the said nanoparticles.

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2011

Dr. Deepthy Menon, Chennazhi, K., Mohan, C. C., R, S. P., and Shantikumar V Nair, “THE ART, METHOD AND MANNER OF TITANIUM-BASED CARDIOVASCULAR STENTS WITH NANOSTRUCTURED SURFACES”, U.S. Patent 2355/CHE/20112011.

2011

Dr. Manzoor K., Retnakumari, A., and Shantikumar V Nair, “The Art, Method, Maner, Process and System of Protien-Sorafenib Nanomedicine”, U.S. Patent 3455/CHE/20112011.

2011

Shantikumar V Nair, Dr. Jayakumar Rangasamy, Lakshmanan, V. - K., Kumar, P. T. Sudhess, Snima, K. S., and Ramya, C., “THE ART, METHOD, MANNER, PROCESS AND SYSTEM OF PREPARATION OF PROPOLIS NANOPARTICLES FOR ANTI-CANCEROUS AND ANTIBACTERIAL APPLICATIONS”, U.S. Patent 907/CHE/20112011.

2011

Dr. Sabitha M., Dr. Jayakumar Rangasamy, Shantikumar V Nair, Amrita, N., N Rejinold, S., and Lakshmanan, V. Kumar, “The art, method, manner, process and system of preparation of curcumin loaded chitin nanogels for skin penetration”, U.S. Patent 2353/CHE/2011 A2011.[Abstract]


A method for the preparation of chitin nanogel loaded with curcumin without using any organic solvents or surfactants which show deep skin penetration and increased bioavailability of curcumin at sites of cancer with low pH.

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2010

Dr. Jayakumar Rangasamy, Dr. Manzoor K., Shantikumar V Nair, Lakshmanan, V. K., Kumar, P. T. Sudheesh, and Abhilash, S., “The Art, Method, Manner, Process and System of Chitosan hydrogel / Nano Zinc Oxide Membranes for Wound Dressing Applications”, U.S. Patent 1025/CHE/20102010.

2010

Dr. Jayakumar Rangasamy, Manzoor, K., Shantikumar V Nair, Lakshmanan, V. K., Kumar, P. T. Sudheesh, and Abhilash, S., “THE ART, MANNER, METHOD AND PROCESS OF PREPARATION OF CHITOSAN SPONGE CONTAINING THE HERB COLEUS PLECTRANTBUS AS A WOUND DRESSING”, U.S. Patent 3012/CHE/20102010.

2010

Shantikumar V Nair and Lekha, P., “The Art, Method, Manner, Process and Design of a double-side illumination photovoltaic cell and method for making the same”, U.S. Patent 2447/CHE/20102010.

2010

Shantikumar V Nair, “The Art, Method, Manner, Process and System of Photo Voltaic Panel Design using Vertically Aligned Panels for improved efficiency”, U.S. Patent 2446/CHE/2010 2010.

Publication Type: Conference Proceedings

Year of Publication Title

2018

H. Menon, Gopakumar, G., Vijayaraghavan, S. N., Dr. Mariyappan Shanmugam, Ashok, A., and Shantikumar V Nair, “Effect of 2D Layered WS2 Nanoflakes on SnO2 Based Dye Sensitized Solar Cell Performance”, Third International Conference on Nanomaterials: Synthesis, Characterization and Applications. Mahatma Gandhi University, Kottayam, 2018.

2018

A. Ashok, Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “Studies on Defect Mediated Charge Transport and Recombination Dynamics in SnO2 Based Dye Sensitized Solar Cells”, Third International Conference on Nanomaterials: Synthesis, Characterization and Applications. Mahatma Gandhi University, Kottayam, Kerala, 2018.

Publication Type: Book

Year of Publication Title

2013

S. Kalluri, Asha, A. M., Sivakumar, N., Parvathy, S., Kim, T. N., Subramanian, K. R. V., Balakrishnan, A., and Shantikumar V Nair, Electrospun Nanofibers of Polyaniline-carbon Black Composite for Conductive Electrode Applications. Nova Science Publishers, Inc., 2013, pp. 181-202.[Abstract]


Polyaniline is known for its good thermal stability, high electrical conductivity and corrosion resistance. Incorporating fillers like carbon black as secondary phases enhances these properties, making it available for electrical and electronics applications. Introducing these composites as nanofibers on an electrode overlay can be beneficial from electron mobility standpoint. Electrospinning is one of the commonly pursued methods for synthesizing nanofibers. However, it is difficult to electrospin polyaniline alone as it is insoluble in organic/inorganic solvents. Inorder to overcome this problem, polyaniline is blended with binder solutions like polyvinyl alcohol (PVA). But, the presence of an insulating carrier like PVA introduces a percolation threshold (threshold voltage beyond which a material starts behaving as a conductor) which can affect applications where high conductivity is required. The problem adds up when carbon black is introduced into the polyaniline matrix. Carbon black tends to create a solid gel when mixed with PVA resulting in a high viscosity solution which makes this blend not suitable for electrospinning. In the present chapter, highly conductive porous ( 70%) polyaniline-carbon black composite nanofiber mats were fabricated via electrospinning. The fiber mat was electrospun using polyvinyl alcohol as carrier solution which was later decomposed at  230 °C to get a complete conducting nanofiber network and did not result in any structural collapse. This heat treatment reduced the fiber diameter from  240 nm to  170 nm, increased surface pore size from 0.4±0.08 μm to 1.3±0.35 μm and the porosity of the mat increased from 40±1.2% to 75±2%. The removal of the carrier phase in the composite was confirmed by Fourier transform infrared spectroscopy. The spatial specific conductance measurements using scanning electrochemical microscopy showed that the presence of polyvinyl alcohol could introduce percolation threshold and removal of the same by heat treatment substantially reduced the percolation threshold and increased the fiber mat conductance. The heat-treated fibers showed four times increase in specific conductance values on removal of carrier phase from the fiber structure. The present chapter discusses the role of carbon black in polyaniline matrix, which can be beneficial as conductive electrode applications in electronic and photovoltaic storage devices. © 2013 by Nova Science Publishers, Inc. All rights reserved.

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