Centre for Nanosciences
Amrita Institute of Medical Sciences,
Amrita Vishwa Vidyapeetham
AIMS Ponekkara P. O., Kochi, Kerala - 682 041, India.

0484 285 8750
researchsecretary@aims.amrita.edu
 

 

Dr. Manitha B. Nair is an Associate Professor at Amrita Center for Nanoscience and Molecular Medicine, Kochi. She has completed M.Sc. Biotechnology from Kerala University and Ph. D from SCTIMST, India in the field of tissue engineering and regenerative medicine. She pursued post-doctoral research in Rice University, USA, and in Georgia Institute of Technology, USA. She has also worked in Max Bergmann Centre for Biomaterials, Germany. She has joined as Assistant Professor at Amrita in 2012. Dr. Nair has received many prestigious awards that includes Kerala State Young Scientist Award (2016); MAHE award by Society for Biomaterials and Artificial Organs India (2015); DBT Innovative Young Biotechnology Award (2012); DST Young Scientist Fellowship (2012); Young Scientist Award in Kerala Science Congress (2007); ZEISS Best Photomicrograph Award (20016). She is the founder Life Member of Society for Tissue Engineering and Regenerative Medicine, India; Life Member of Materials Research Society of India & Life member of Indian Society of Nanomedicine. Dr. Nair serves as the reviewer of reputed journals in Nanoscience and Biomedical research.

Dr. Manitha is working on the development and clinical translation of low cost, biomimetic nanomaterials towards musculoskeletal (bone, cartilage, ligament) and intervertebral disc regeneration. She is interested in investigating the signaling cues that support lineage-specific differentiation of mesenchymal stem cells. Her research is also focused on improving the release kinetics of antimicrobial agents in reducing osteomyelitis and implant related infections. Moreover the role of phytochemicals / growth factors in enhancing vascularisation and tissue regeneration is being investigating.

Low Cost Biomimetic Grafts for Musculoskeletal Tissue Regeneration

Every year, millions of patients suffer loss or failure of an organ or tissue as a result of accident or disease. Tissue or organ transplantation is a commonly accepted norm under these circumstances, but its availability is very less. In our lab, we focus on the fabrication of extracellular matrix mimicking nanocomposite scaffolds that provide structural support and proliferating cues for stem cells to form new tissue. The scaffolds are tuned to induce lineage specific differentiation of mesenchymal stem cells. Specifically, we focus on the development of biomaterials for bone and cartilage tissue, its GMP scaling up and clinical translation.

Functional and Vascularized Biomaterials for Critical-sized Defects

One of the greatest challenges in tissue engineering is to develop functional and vascularized large-scale tissue substitutes. In our lab, we functionalize biomaterials for use as delivery systems for growth factors, small molecules and phytochemicals. The incorporation of these biosignalling cues has shown to enhance the functionality of endothelial cells, leading to better blood vessel formation and tissue regeneration in critical sized defects in animal models within shorter period.

Biodegradable Antibiotic-Impregnated Scaffold for Osteomyelitis Treatment

Osteomyelitis is a severe, progressive inflammatory process caused by Staphylococcus aureus bacteria. Management of infected bone with local antibiotic delivery system (PMMA) achieves therapeutic drug concentration at the site, however PMMA beads are non-biodegradable. Our lab focus on the development of biodegradable antibiotic loaded scaffold for reducing bacterial contamination in chronic osteomyelitis, so as to avoid revision surgery.

Osseointegration Studies of Metallic Implants with Bone Tissue

Osseointegration describes direct anchorage and integration of a Ti or stainless steel implant (orthopaedic or dental) with living bone. The success of this adaptation depends on several factors, including the organization and density of the bone surrounding the implant, the implant design, and surgical technique used. Our group evaluates the impact of quality of bone in determining the primary and secondary stability of dental implants.

Intervertebral Disc Regeneration

Degeneration of the intervertebral disc causes low back pain in around 80% of adults. Current treatments include spinal fusion and artificial disc replacement, but these may alter the biomechanics of adjacent discs and cause subsequent degeneration. In our lab, research is ongoing to develop mechanically stable and biofunctional injectible composite hydrogels for intervertebral disc regeneration.


Biomimetic bone graft developed in our Lab could support the adhesion and proliferation of mesenchymal stem cells in vitro as well as bone regeneration in vivo

Dr. Manju V - Ph. D Student

  • Professor at Amrita School of Dentistry
  • Year of joining: 2013
  • Research area: Native bone augmentation with biomimetic biomaterials and osseointegration using dental implants
  • Email: manjuv@aims.amrita.edu

Amit G Krishnan - Ph. D Student

  • M. Tech (Biotechnology)
  • Year of joining : 2013
  • Research area: Bone regeneration in osteomyelitic bone using antibiotic loaded biodegradable scaffolds
  • Email: amitgk@aims.amrita.edu

Shruthy Kuttappan - Ph. D Student

  • M tech (Molecular Medicine)
  • Year of joining: 2014
  • Research area: Influence of functionalized biomaterials on enhancing vascularisation and tissue regeneration in critical sized defects
  • Email: sruthik20909@aims.amrita.edu

Haseena PA - Junior Research Fellow

  • M. Sc (Biotechnology)
  • Year of joining: 2018
  • Research area: Biomimetic scaffolds for bone tissue regeneration

Dr. Unnikrishnan PS – Postdoctoral Fellow

  • Ph. D (Biotechnology)
  • Year of joining: 2018
  • Research area: GMP development and clinical translational of bone grafts for tissue regeneration
  • Email: unnikrishnan26689@aims.amrita.edu

Aswathy SH – M. Tech Student

  • M. Tech (Nanomedical sciences)
  • Batch: 2016-2018
  • Research area: Cell response on scaffolds derived from plant origin

Dr. Anjali - MD

  • Master of Dentistry
  • Batch: 2017-2019
  • Research area: Evaluation of antimicrobial effect of phytochemicals

Alumni

Dr. Anitha A Nair – Ph. D Student

  • Ph. D (Nanobioengineering)
  • Period of Research: 2012 – 2017
  • Research area: Development of fiber reinforced nanocomposite scaffolds for bone regeneration
  • Current status: Postdoc in Université catholique de Louvain, Belgium

Dr. Chandini C Mohan – Postdoctoral Fellow

  •  Ph. D (Nanobioengineering)
  • Period of Research: 2017 - 2018
  • Research area: Translational Research in Bone Tissue Engineering.

M.Tech. / M.Sc. Students

  • Dr. Arunkumar T, MS Ortho, Amrita School of Medicine (2014-2017), Current Status: Junior Consultant, Orthopaedics
  • Ms. Aathira, M. Pharm, Amrita School of Pharmacy (2015-2017), Current Status: Production executive at Zenotech Laboratories Ltd, Hyderabad
  • Ms. Sowmya, M. Sc Biotechnology, Amrita School of Biotechnology (2015 – 2017)
  • Ms. Shilpa, M. Sc Biotechnology, Amrita School of Biotechnology (2015 – 2017)
  • Dr. Parvathi K, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2015 – 2017), Current Status: Clinical practice
  • Ms. Radhika Unnikrishnan, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2014 – 2016)
  • Mr. Dennis Mathew, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2014 – 2016), Current Status: Staff engineer at Amrita Center for Nanoscience, Kochi
  • Ms. Anu Mohandas, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2013 – 2015)
  • Ms. Anjana J, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2013 – 2015), Current Status: Ph. D Scholar at Amrita Center for Nanosceince, Kochi
  • Ms. Prajuna Vijayan, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2012 – 2014), Current Status: Sr. Clinical Project Associate at Covance CLS, Bangalore
  • Ms. Nancy David, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2012 – 2014), Current Status: Ph. D Scholar at Anna University
  • Ms. Lakshmi Jayaram, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2012 – 2014), Current Status: Sr .Clinical Process Associate at IQVIA, Bangalore
  • Dr. Bibi Halima, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2011 - 2013), Current Status: Clinical practice
  • Ms. Elmy Elizatbeth, M. Tech (Nanomedical Science), Amrita Center for Nanoscience (2011 - 2013)

Publications

Publication Type: Journal Article

Year of Publication Title

2018

S. Kuttappan, Anitha, A., Minsha Mallika Gopi, Menon, P. M., Sivanarayanan, T. B., Dr. Lakshmi Sumitra, and Dr. Manitha B. Nair, “BMP2 Expressing Genetically Engineered Mesenchymal Stem Cells on Composite Fibrous Scaffolds for Enhanced bone Regeneration in Segmental Defects”, Materials Science and Engineering: C, vol. 85, pp. 239 - 248, 2018.[Abstract]


The treatment of critical sized bone defect remains a significant challenge in orthopedics. The objective of the study is to evaluate the effect of the combination of bone morphogenetic protein 2 (BMP2) expressing genetically engineered mesenchymal stem cells (MSCs) [MSCs engineered using a multimam vector, pAceMam1, an emerging gene delivery vector] and an osteoconductive scaffold [silica coated nanohydroxyapatite-gelatin reinforced with fibers] in enhancing bone regeneration in critical sized segmental defects. The scaffold with transfected MSCs showed significantly higher viability, proliferation and osteogenic differentiation in vitro. Further, this group augmented union and new bone formation in critical sized rat femoral segmental defect at 12 weeks when compared to control groups (scaffold with MSCs and scaffold alone). These data demonstrated that the MSCs engineered for transient expression of BMP2 can improve the repair of segmental defects, which paves an avenue for using pAceMam1 as a vector for bone tissue regeneration.

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2017

A. A, Menon, D., B, S. T., Koyakutty, M., Mohan, C. C., Nair, S. V., and Dr. Manitha B. Nair, “Bioinspired Composite Matrix Containing Hydroxyapatite–Silica Core–Shell Nanorods for Bone Tissue Engineering”, ACS Applied Materials & Interfaces, vol. 9, no. 32, pp. 26707–26718, 2017.[Abstract]


Development of multifunctional bioinspired scaffolds that can stimulate vascularization and regeneration is necessary for the application in bone tissue engineering. Herein, we report a composite matrix containing hydroxyapatite (HA)–silica core–shell nanorods with good biocompatibility, osteogenic differentiation, vascularization, and bone regeneration potential. The biomaterial consists of a crystalline, rod-shaped nanoHA core with uniform amorphous silica sheath (Si–nHA) that retains the characteristic phases of the individual components, confirmed by high-resolution transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The nanorods were blended with gelatinous matrix to develop as a porous, composite scaffold. The viability and functionality of osteogenically induced mesenchymal stem cells as well as endothelial cells have been significantly improved through the incorporation of Si–nHA within the matrix. Studies in the chicken chorioallantoic membrane and rat models demonstrated that the silica-containing scaffolds not only exhibit good biocompatibility, but also enhance vascularization in comparison to the matrix devoid of silica. Finally, when tested in a critical-sized femoral segmental defect in rats, the nanocomposite scaffolds enhanced new bone formation in par with the biomaterial degradation. In conclusion, the newly developed composite biomimetic scaffold may perform as a promising candidate for bone tissue engineering applications.

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2017

A. Mohandas, Krishnan, A. G., Dr. Raja Biswas, Dr. Deepthy Menon, and Dr. Manitha B. Nair, “Antibacterial and cytocompatible nanotextured Ti surface incorporating silver via single step hydrothermal processing”, Materials Science and Engineering C, vol. 75, pp. 115-124, 2017.[Abstract]


Nanosurface modification of Titanium (Ti) implants and prosthesis is proved to enhance osseointegration at the tissue–implant interface. However, many of these products lack adequate antibacterial capability, which leads to implant loosening. As a curative strategy, in this study, nanotextured Ti substrates embedded with silver nanoparticles were developed through a single step hydrothermal processing in an alkaline medium containing silver nitrate at different concentrations (15, 30 and 75 μM). Scanning electron micrographs revealed a non-periodically oriented nanoleafy structure on Ti (TNL) decorated with Ag nanoparticles (nanoAg), which was verified by XPS, XRD and EDS analysis. This TNLAg substrate proved to be mechanically stable upon nanoindentation and nanoscratch tests. Silver ions at detectable levels were released for a period of 28 days only from substrates incorporating higher nanoAg content. The samples demonstrated antibacterial activity towards both Escherichia coli and Staphylococcus aureus, with a more favorable response to the former. Simultaneously, Ti substrates incorporating nanoAg at all concentrations supported the viability, proliferation and osteogenic differentiation of mesenchymal stem cells. Overall, nanoAg incorporation into surface modified Ti via a simple one-step thermochemical method is a favorable strategy for producing implants with dual characteristics of antibacterial activity and cell compatibility. © 2017 Elsevier B.V.

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2016

A. J, Kuttappan, S., Keyan, K. S., and Dr. Manitha B. Nair, “Evaluation of osteoinductive and endothelial differentiation potential of Platelet-Rich Plasma incorporated Gelatin-Nanohydroxyapatite Fibrous Matrix”, Journal of Biomedical Materials Research Part B: Applied Biomaterials, vol. 104, no. 4, pp. 771-781, 2016.[Abstract]


In this study, platelet-rich plasma (PRP) was incorporated into gelatin-nanohydroxyapatite fibrous scaffold in two forms (PRP gel as coating on the scaffold [PCSC] and PRP powder within the scaffold [PCSL] and investigated for (a) growth factor release; (b) stability of scaffold at different temperature; (c) stability of scaffold before and after ETO sterilization; and (d) osteogenic and endothelial differentiation potential using mesenchymal stem cells (MSCs). PCSC demonstrated a high and burst growth factor release initially followed by a gradual reduction in its concentration, while PCSL showed a steady state release pattern for 30 days. The stability of growth factors released from PCSL was not altered either through ETO sterilization or through its storage at different temperature. PRP-loaded scaffolds induced the differentiation of MSCs into osteogenic and endothelial lineage without providing any induction factors in the cell culture medium and the differentiation rate was significantly higher when compared to the scaffolds devoid of PRP. PCSC performed better than PCSL. In general, PRP in combination with composite fibrous scaffold could be a promising candidate for bone tissue engineering applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 771–781, 2016.

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2015

A. M. Henslee, Yoon, D. M., Lu, B. Y., Yu, J., Arango, A. A., Marruffo, L. P., Seng, L., Anver, T. D., Ather, H., Dr. Manitha B. Nair, and , “Characterization of an injectable, degradable polymer for mechanical stabilization of mandibular fractures”, Journal of Biomedical Materials Research Part B: Applied Biomaterials, vol. 103, pp. 529–538, 2015.[Abstract]


This study investigated the use of injectable poly(propylene fumarate) (PPF) formulations for mandibular fracture stabilization applications. A full factorial design with main effects analysis was employed to evaluate the effects of the PPF:N-vinyl pyrrolidone (NVP, crosslinking agent) ratio and dimethyl toluidine (DMT, accelerator) concentration on key physicochemical properties including setting time, maximum temperature, mechanical properties, sol fraction, and swelling ratio. Additionally, the effects of formulation crosslinking time on the mechanical and swelling properties were investigated. The results showed that increasing the PPF:NVP ratio from 3:1 to 4:1 or decreasing the DMT concentration from 0.05 to 0.01 v/w % significantly decreased all mechanical properties as well as significantly increased the sol fraction and swelling ratio. Also, increasing the crosslinking time at 37°C from 1 to 7 days significantly increased all mechanical properties and decreased both the sol fraction and swelling ratio. This study further showed that the flexural stiffness of ex vivo stabilized rabbit mandibles increased from 1.7 ± 0.3 N/mm with a traditional mini-plate fixator to 14.5 ± 4.1 N/mm for the 4:1 (0.05 v/w % DMT) PPF formulation at day 1. Overall, the formulations tested in this study were found to have properties suitable for potential further consideration in mandibular fracture fixation applications. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 529–538, 2015.

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2015

Dr. Manitha B. Nair and Elizabeth, E., “Applications of Titania Nanotubes in Bone Biology”, Journal of Nanoscience and Nanotechnology, vol. 15, pp. 939–955, 2015.[Abstract]


Orthopedic implants, including artificial joints and fracture fixation devices, have helped to restore the physical independence of many patients, thereby improving the quality of their lives. Titania (Ti) and its alloys are better implant materials than stainless steel and Co–Cr alloys owing to their superior mechanical properties and biocompatibility; however, Ti-based implants may sometimes fail, leading to repeated surgeries. With the recent advancements in nanotechnology, the nanosurface modifications of Ti, especially in the form of Ti nanotubes (TNTs), have drastically improved the properties of orthopedic implants. In this review, we have summarized the fabrication of Ti nanotubes by electrochemical anodization and their influence on osteoblast cells and staphylococcus aureus. In addition, we have discussed the corrosion resistance of Ti nanotubes.

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2015

B. Halima Shamaz, Anitha, A., Vijayamohan, M., Kuttappan, S., Nair, S., 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

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

Dr. Manitha B. Nair, Baranwal, G., Vijayan, P., Keyan, K. S., and Dr. Jayakumar Rangasamy, “Composite hydrogel of chitosan-poly(hydroxybutyrate-co-valerate) with chondroitin sulfate nanoparticles for nucleus pulposus tissue engineering”, Colloids and Surfaces B: Biointerfaces, vol. 136, pp. 84-92, 2015.[Abstract]


Intervertebral disc degeneration, occurring mainly in nucleus pulposus (NP), is a leading cause of low back pain. In seeking to mitigate this condition, investigators in the field of NP tissue engineering have increasingly studied the use of hydrogels. However, these hydrogels should possess appropriate mechanical strength and swelling pressure, and concurrently support the proliferation of chondrocyte-like cells. The objective of this study was to develop and validate a composite hydrogel for NP tissue engineering, made of chitosan-poly(hydroxybutyrate- co-valerate) (CP) with chondroitin sulfate (CS) nanoparticles, without using a cross linker. The water uptake ability, as well as the viscoelastic properties of this composite hydrogel, was similar to native tissue, as reflected in the complex shear modulus and stress relaxation values. The hydrogel could withstand varying stress corresponding to daily activities like lying down (0.01. MPa), sitting (0.5. MPa) and standing (1.0. MPa) under dynamic conditions. The hydrogels were stable in PBS for 2 weeks and its stiffness, elastic and viscous modulus did not alter significantly during this period. Both CP and CP-CS hydrogels could assist the viability and adhesion of adipose derived rat mesenchymal stem cells (ADMSCs). The viability and chondrogenic differentiation of MSCs was significantly enhanced in presence of CS nanoparticles. Thus, CS nanoparticles-incorporated chitosan-PHBV hydrogels offer great potential for NP tissue engineering. © 2015 Elsevier B.V.

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2015

A. G. Krishnan, Jayaram, L., Dr. Raja Biswas, and Dr. Manitha B. Nair, “Evaluation of antibacterial activity and cytocompatibility of ciprofloxacin loaded gelatin-hydroxyapatite scaffolds as a local drug delivery system for osteomyelitis treatment”, Tissue Engineering - Part A, vol. 21, pp. 1422-1431, 2015.[Abstract]


Surgical debridement of the dead bone and subsequent systemic antibiotic therapy is often ineffective in eliminating Staphylococcus aureus infections in osteomyelitic patients. The recurrence of S. aureus infection is mainly due to the intracellular growth of bacterial colonies within osteoblast cells that protect the organism from extracellular host defences and/or antibiotic therapy. In this study, porous gelatin-hydroxyapatite (HAP) scaffolds with various amounts of ciprofloxacin (1, 2, 5, and 10 wt%) were fabricated by freeze-drying technique and the release of the antibiotic was characterized, as was the efficacy of the released antibiotic against methicillin-sensitive and methicillin-resistant S. aureus. Furthermore, the impact of the released antibiotic on the viability and osteogenic differentiation of human adipose-derived mesenchymal stem cells (ADMSCs) cultured on the scaffolds were assessed. Finally, the efficacy of the released ciprofloxacin to enter the cells and abate intracellularly located S. aureus was evaluated. All the groups of CGHA scaffolds displayed sustained release of ciprofloxacin against S. aureus for 60 days above the minimum inhibitory concentration for the target species with zero-order kinetics and Korsmeyer-Peppas models. While comparing, the released antibiotic from CGHA5 scaffolds was found to be effective at reducing S. aureus through the study period, without detrimental effects on human ADMSC viability or osteogenic potential. When stem cells internalized with S. aureus were cultured onto the drug-loaded scaffolds, a significant reduction in the colony count of internalized bacteria was observed, resulting in the osteogenic differentiation capability of those cells. Our results clearly demonstrate that the ciprofloxacin incorporated gelatin-HAP scaffolds, which were cytocompatible and could target both intracellular and extracellular S. aureus, defining its potential to be used as local drug delivery system. © Copyright 2015, Mary Ann Liebert, Inc. 2015.

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2014

Dr. Manitha B. Nair and Krishnan, A., “Antibiotic releasing biodegradable scaffolds for osteomyelitis”, Current drug delivery, vol. 11, pp. 687–700, 2014.[Abstract]


Osteomyelitis is characterized by progressive inflammatory bone degeneration. In the management of chronic osteomyelitis, it is necessary to remove the infected bone tissue followed by implantation of an antibiotic releasing biomaterial that can release antibiotic locally for long periods of time. The main carrier used in clinics for this application is polymethylmethacrylate (PMMA) (Eg. Septopal beads). However, major drawback is the need of an additional surgery to remove the beads after therapy, as PMMA is not biodegradable. This necessitates the requirement of biodegradable carrier systems that can release antibiotics and simultaneously support debrided bone formation. This review summarizes biodegradable carrier systems that have been reported for the localised treatment and prophylaxis of osteomyelitis.

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2014

E. Elizabeth, Baranwal, G., Krishnan, A. G., Menon, D., and Dr. Manitha B. Nair, “ZnO nanoparticle incorporated nanostructured metallic titanium for increased mesenchymal stem cell response and antibacterial activity”, Nanotechnology, vol. 25, 2014.[Abstract]


Recent trends in titanium implants are towards the development of nanoscale topographies that mimic the nanoscale properties of bone tissue. Although the nanosurface promotes the integration of osteoblast cells, infection related problems can also occur, leading to implant failure. Therefore it is imperative to reduce bacterial adhesion on an implant surface, either with or without the use of drugs/antibacterial agents. Herein, we have investigated two different aspects of Ti surfaces in inhibiting bacterial adhesion and concurrently promoting mammalian cell adhesion. These include (i) the type of nanoscale topography (Titania nanotube (TNT) and Titania nanoleaf (TNL)) and (ii) the presence of an antibacterial agent like zinc oxide nanoparticles (ZnOnp) on Ti nanosurfaces. To address this, periodically arranged TNT (80-120 nm) and non-periodically arranged TNL surfaces were generated by the anodization and hydrothermal techniques respectively, and incorporated with ZnOnp of different concentrations (375 μM, 750 μM, 1.125 mM and 1.5 mM). Interestingly, TNL surfaces decreased the adherence of staphylococcus aureus while increasing the adhesion and viability of human osteosarcoma MG63 cell line and human mesenchymal stem cells, even in the absence of ZnOnp. In contrast, TNT surfaces exhibited an increased bacterial and mammalian cell adhesion. The influence of ZnOnp on these surfaces in altering the bacterial and cell adhesion was found to be concentration dependent, with an optimal range of 375-750 μM. Above 750 μM, although bacterial adhesion was reduced, cellular viability was considerably affected. Thus our study helps us to infer that nanoscale topography by itself or its combination with an optimal concentration of antibacterial ZnOnp would provide a differential cell behavior and thereby a desirable biological response, facilitating the long term success of an implant. More »»

2011

Dr. Manitha B. Nair, Kretlow, J. D., Mikos, A. G., and F Kasper, K., “Infection and tissue engineering in segmental bone defects—a mini review”, Current Opinion in Biotechnology, vol. 22, pp. 721 - 725, 2011.[Abstract]


As tissue engineering becomes more of a clinical reality through the ongoing bench to bedside transition, research in this field must focus on addressing relevant clinical situations. Although most in vivo work in the area of bone tissue engineering focuses on bone regeneration within sterile, surgically created defects, there is a growing need for the investigation of bone tissue engineering approaches within contaminated or scarred wound beds, such as those that may be encountered following traumatic injury or during delayed reconstruction/regeneration. Significant work has been performed in the area of local drug delivery via biomaterial carriers, but there is little intersection in the available literature between antibiotic delivery and tissue regeneration. In this review, we examine recent advances in segmental bone defect animal models, bone tissue engineering, and drug delivery with the goal of identifying promising approaches and areas needing further investigation towards developing both a better understanding of and new tissue engineering approaches for addressing infection control while simultaneously initiating bone regeneration.

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2011

A. M. Henslee, Spicer, P. P., Yoon, D. M., Dr. Manitha B. Nair, Meretoja, V. V., Witherel, K. E., Jansen, J. A., Mikos, A. G., and Kasper, F. K., “Biodegradable composite scaffolds incorporating an intramedullary rod and delivering bone morphogenetic protein-2 for stabilization and bone regeneration in segmental long bone defects”, Acta Biomaterialia, vol. 7, pp. 3627 - 3637, 2011.[Abstract]


In this study, a two-part bone tissue engineering scaffold was investigated. The scaffold consists of a solid poly(propylene fumarate) (PPF) intramedullary rod for mechanical support surrounded by a porous PPF sleeve for osseointegration and delivery of poly(dl-lactic-co-glycolic acid) (PLGA) microspheres with adsorbed recombinant human bone morphogenetic protein-2 (rhBMP-2). Scaffolds were implanted into critical size rat segmental femoral defects with internal fixation for 12weeks. Bone formation was assessed throughout the study via radiography, and following euthanasia, via microcomputed tomography and histology. Mechanical stabilization was evaluated further via torsional testing. Experimental implant groups included the PPF rod alone and the rod with a porous PPF sleeve containing PLGA microspheres with 0, 2 or 8μg of rhBMP-2 adsorbed onto their surface. Results showed that presence of the scaffold increased mechanical stabilization of the defect, as evidenced by the increased torsional stiffness of the femurs by the presence of a rod compared to the empty defect. Although the presence of a rod decreased bone formation, the presence of a sleeve combined with a low or high dose of rhBMP-2 increased the torsional stiffness to 2.06±0.63 and 1.68±0.56N·mm, respectively, from 0.56±0.24N·mm for the rod alone. The results indicate that, while scaffolds may provide structural support to regenerating tissues and increase their mechanical properties, the presence of scaffolds within defects may hinder overall bone formation if they interfere with cellular processes.

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2011

Dr. Manitha B. Nair, Varma, H. K., Mohanan, P. V., and John, A., “Tissue-engineered triphasic ceramic coated hydroxyapatite induced bone formation and vascularization at an extraskeletal site in a rat model”, Bulletin of Materials Science, vol. 34, pp. 1721–1731, 2011.[Abstract]


Tissue-engineered bone regeneration has attracted much attention because of its high clinical demand for restoration of injured tissues. In the present study, we have evaluated the capability of bare (without cells) and tissue-engineered (with osteogenic-induced rat Mesenchymal Stem Cells (MSCs)) bioactive ceramics such as hydroxyapatite (HA) and triphasic ceramic-coated hydroxyapatite (HASi) to mediate vascularisation and osteoinduction at an extraskeletal site of rat model. The viability, proliferation and osteogenic differentiation of MSCs on the scaffolds were assessed in vitro and thereby established the capability of HASi in providing a better structural habitat than HA. The vascular invasion was relatively low in bare and tissue-engineered HA at 2 and 4 weeks. Interestingly, the implantation site was well vascularised with profuse ingrowth of blood capillaries in HASi groups, with preference for tissue-engineered HASi groups. Similarly, neo-osteogenesis studies were shown only by tissue-engineered HASi groups. The ingrowth of numerous osteoblast-like cells was seen around and within the pores of the material in bare HASi and tissue-engineered HASi groups (very low cellular infiltration in bare HA groups), but there was no osteoid deposition. The positive impact in forming bone in tissue-engineered HASi groups is attributable to the scaffold and to the cells, with the first choice for scaffold because both HA and HASi were engineered simultaneously with the cells from same source and same passage. Thus, highly porous interconnected porous structure and appropriate chemistry provided by HASi in combination with osteogenic-induced MSCs facilitated better vascularisation that lead to neo-osteogenesis.

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2010

Dr. Manitha B. Nair, S, M., S, N., K, S., M, J., and A, J., “Adult Stem Cells on Methacrylic Acid Grafted Cocoon Silky Fibrous Scaffolds”, Trends in Biomaterials and Artificial Organs , vol. 23, no. 3, pp. 137-144, 2010.

2010

S. I. Ranganathan, Yoon, D. M., Henslee, A. M., Dr. Manitha B. Nair, Smid, C., F. Kasper, K., Tasciotti, E., Mikos, A. G., Decuzzi, P., and Ferrari, M., “Shaping the micromechanical behavior of multi-phase composites for bone tissue engineering”, Acta Biomaterialia, vol. 6, pp. 3448 - 3456, 2010.[Abstract]


Mechanical stiffness is a fundamental parameter in the rational design of composites for bone tissue engineering in that it affects both the mechanical stability and the osteo-regeneration process at the fracture site. A mathematical model is presented for predicting the effective Young’s modulus (E) and shear modulus (G) of a multi-phase biocomposite as a function of the geometry, material properties and volume concentration of each individual phase. It is demonstrated that the shape of the reinforcing particles may dramatically affect the mechanical stiffness: E and G can be maximized by employing particles with large geometrical anisotropy, such as thin platelet-like or long fibrillar-like particles. For a porous poly(propylene fumarate) (60% porosity) scaffold reinforced with silicon particles (10% volume concentration) the Young’s (shear) modulus could be increased by more than 10 times by just using thin platelet-like as opposed to classical spherical particles, achieving an effective modulus E ∼ 8GPa (G ∼ 3.5GPa). The mathematical model proposed provides results in good agreement with several experimental test cases and could help in identifying the proper formulation of bone scaffolds, reducing the development time and guiding the experimental testing.

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2009

Dr. Manitha B. Nair, Bernhardt, A., Lode, A., Heinemann, C., Thieme, S., Hanke, T., Varma, H., Gelinsky, M., and John, A., “A bioactive triphasic ceramic-coated hydroxyapatite promotes proliferation and osteogenic differentiation of human bone marrow stromal cells”, Journal of Biomedical Materials Research Part A, vol. 90, pp. 533–542, 2009.[Abstract]


Hydroxyapatite (HA) ceramics are widely used as bone graft substitutes because of their biocompatibility and osteoconductivity. However, to enhance the success of therapeutic application, many efforts are undertaken to improve the bioactivity of HA. We have developed a triphasic, silica-containing ceramic-coated hydroxyapatite (HASi) and evaluated its performance as a scaffold for cell-based tissue engineering applications. Human bone marrow stromal cells (hBMSCs) were seeded on both HASi and HA scaffolds and cultured with and without osteogenic supplements for a period of 4 weeks. Cellular responses were determined in vitro in terms of cell adhesion, viability, proliferation, and osteogenic differentiation, where both materials exhibited excellent cytocompatibility. Nevertheless, an enhanced rate of cell proliferation and higher levels of both alkaline phosphatase expression and activity were observed for cells cultured on HASi with osteogenic supplements. These findings indicate that the bioactivity of HA endowed with a silica-containing coating has definitely influenced the cellular activity, projecting HASi as a suitable candidate material for bone regenerative therapy. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

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2009

Dr. Manitha B. Nair, Varma, H. K., Menon, K. V., Shenoy, S. J., and John, A., “Tissue regeneration and repair of goat segmental femur defect with bioactive triphasic ceramic-coated hydroxyapatite scaffold”, Journal of Biomedical Materials Research Part A, vol. 91A, no. 3, pp. 855–865, 2009.[Abstract]


Bone tissue engineering which is a developing and challenging field of science, is expected to enhance the regeneration and repair of bone lost from injury or disease and ultimately to gain its aesthetic contour. The objective of this study was to fabricate a tissue-engineered construct in vitro using a triphasic ceramic-coated hydroxypatite (HASi) in combination with stem cells and to investigate its potential in healing segmental defect in goat model. To accomplish this attempt, mesenchymal stem cells isolated from goat bone marrow were seeded onto HASi scaffolds and induced to differentiate into the osteogenic lineage in vitro. Scanning electron microscopy and light microscopy revealed adhesion and spread-out cells, which eventually formed a cell-sheet like canopy over the scaffold. Cells migrated and distributed themselves within the internal voids of the porous ceramic. Concurrently, the neo-osteogenesis of the tissue-engineered construct was validated in vivo in comparison with bare HASi (without cells) in goat femoral diaphyseal segmental defect (2 cm) at 4 months postimplantation through radiography, computed tomography, histology, histomorphometry, scanning electron microscopy and inductively coupled plasma spectrometry. Good osteointegration and osteoconduction was observed in bare and tissue-engineered HASi. The performance of tissue-engineered HASi was better and faster which was evident by the lamellar bone organization of newly formed bone throughout the defect together with the degradation of the material. On the contrary with bare HASi, immature woven bony bridges still intermingled with scattered small remnants of the material was observed in the mid region of the defect at 4 months. Encouraging results from this preclinical study has proved the capability of the tissue-engineered HASi as a promising candidate for the reconstruction of similar bony defects in humans. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

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2009

Dr. Manitha B. Nair, Varma, H. K., John, A., Menon, V., and Shenoy, S., “Reconstruction of goat femur segmental defects using triphasic ceramic-coated hydroxyapatite in combination with autologous cells and platelet-rich plasma”, Acta Biomater , vol. 5, no. 5, 2009.[Abstract]


Segmental bone defects resulting from trauma or pathology represent a common and significant clinical problem. In this study, a triphasic ceramic (calcium silicate, hydroxyapatite and tricalcium phosphate)-coated hydroxyapatite (HASi) having the benefits of both HA (osteointegration, osteoconduction) and silica (degradation) was used as a bone substitute for the repair of segmental defect (2 cm) created in a goat femur model. Three experimental goat femur implant groups--(a) bare HASi, (b) osteogenic-induced goat bone marrow-derived mesenchymal stem cells cultured HASi (HASi+C) and (c) osteogenic-induced goat bone marrow-derived mesenchymal stem cells cultured HASi+platelet-rich plasma (HASi+CP)--were designed and efficacy performance in the healing of the defect was evaluated. In all the groups, the material united with host bone without any inflammation and an osseous callus formed around the implant. This reflects the osteoconductivity of HASi where the cells have migrated from the cut ends of host bone. The most observable difference between the groups appeared in the mid region of the defect. In bare HASi groups, numerous osteoblast-like cells could be seen together with a portion of material. However, in HASi+C and HASi+CP, about 60-70% of that area was occupied by woven bone, in line with material degradation. The interconnected porous nature (50-500 microm), together with the chemical composition of the HASi, facilitated the degradation of HASi, thereby opening up void spaces for cellular ingrowth and bone regeneration. The combination of HASi with cells and PRP was an added advantage that could promote the expression of many osteoinductive proteins, leading to faster bone regeneration and material degradation. Based on these results, we conclude that bare HASi can aid in bone regeneration but, with the combination of cells and PRP, the sequence of healing events are much faster in large segmental bone defects in weight-bearing areas in goats.

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2009

Dr. Manitha B. Nair, Varma, H., Shenoy, S. J., and John, A., “Treatment of Goat Femur Segmental Defects with Silica-Coated Hydroxyapatite—One-Year Follow-Up”, Tissue Engineering Part A, vol. 16, no. 2, pp. 385-391, 2009.[Abstract]


Segmental bone defects caused by tumor resections, trauma, and skeletal abnormalities such as osteomyelitis remain a major problem in orthopedics because of the lack of predictability in attaining functional bone after the treatment. The objective of this study was to propose an indigenous porous biodegradable triphasic ceramic (calcium silicate, tricalcium phosphate, and hydroxyapatite [HA])-coated HA (core) (HASi) for the repair of such segmental defects. With respect to the synthesis of HASi, HA blocks were prepared by wet precipitation, dipped in silica sol (sol gel method), sintered at 1200°C, polished in the form of hollow cylinder (2 cm long with an outer and inner diameter of 2 cm and 7 mm, respectively), and implanted into a 2-cm segmental defect created in the goat femur diaphysis. This study prolonged for 12 uneventful months and thereafter neo-osteogenesis in par with material degradation was analyzed through radiography, histology, histomorphometry, scanning electron microscope (SEM)-energy dispersive spectrum, micro-computed tomography, and inductively coupled plasma spectrometry. HASi proved to be osteoconductive, osteointegrative, and degradative in nature, without the intervention of fibrous tissue formation at the defect site. Histologically, the newly formed bone reorganized, mineralized, and attained the appearance and contour of the original femoral diaphysis in 1 year. The interconnected porous structure with silica composition aided progressive bone regeneration and repair in par with degradation of the material. Thus the study proposed the possibility of using HASi as a suitable material in clinical orthopedic reconstructive surgery, which remains a formidable challenge.

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2008

A. T. Arun Torris, Columbus, K. C. Soumya, Saaj, U. S., Dr. Manitha B. Nair, and Krishnan, K. V., “Evaluation of Biomaterials Using Micro‐Computerized Tomography”, AIP Conference Proceedings, vol. 1050, pp. 68-78, 2008.

2008

A. John, Dr. Manitha B. Nair, Varma, H. K., Bernhardt, A., and Gelinsky, M., “Biodegradation and Cytocompatibility Studies of a Triphasic Ceramic-Coated Porous Hydroxyapatite for Bone Substitute Applications”, International Journal of Applied Ceramic Technology, vol. 5, pp. 11–19, 2008.[Abstract]


Bone defects due to trauma or disease have led to the need for biomaterials as substitutes for tissue regeneration and repair. Herein, we introduce a porous triphasic ceramic-coated hydroxyapatite scaffold (HASi) for such applications. Interestingly, in the degradation experiments with isotonic buffer, HASi showed a significant release of silica with the disappearance of the tricalcium phosphate phase. Furthermore, the material also exhibited cytocompatibility with cultured bone marrow-derived mesenchymal stem cells of human origin. The material chemistry, together with the favorable cellular characteristics, indicates HASi as a promising candidate for critical-size bony defects, which still remains a formidable clinical challenge in the orthopedic scenario.

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2008

Dr. Manitha B. Nair, S. Babu, S., Varma, H. K., and John, A., “A triphasic ceramic-coated porous hydroxyapatite for tissue engineering application”, Acta Biomaterialia, vol. 4, pp. 173 - 181, 2008.[Abstract]


Scaffolds which encourage the incorporation of a cell source for tissue engineering applications are critical determinants for clinical defects. Over the years, a number of biomaterials have emerged for cell support and growth, but only a few have demonstrated clinical efficacy. We therefore investigated an in-house-developed silica-based bioactive ceramic for its ability to support and sustain the growth of bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. For this, MSCs aspirated from goat bone marrow were isolated and culture expanded on a novel triphasic ceramic composite coated hydroxyapatite (HASi) scaffold comprising hydroxyapatite, tricalcium phosphate and calcium silicate. The viability of cells that harbored on and within the material was ensured through fluorescence-activated cell sorting and confocal laser scanning microscope and for their anchorage sites by scanning electron microscopy. Interestingly, over the days in culture, cell–cell interactions gradually morphed into woven cell-sheets that spanned across the surface of the HASi, forming a canopy. To conclude, we have attempted to carry out the preliminary cytocompatibility studies of this novel ceramic to establish its appropriateness for bone tissue engineering application which is an important criterion in orthopaedic transplantation and regenerative surgery.

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2008

Dr. Manitha B. Nair, Varma, H. K., and John, A., “Triphasic ceramic coated hydroxyapatite as a niche for goat stem cell-derived osteoblasts for bone regeneration and repair”, Journal of Materials Science: Materials in Medicine, vol. 20, p. 251, 2008.[Abstract]


Current treatment strategies for the repair or replacement of bone use synthetic implants with stem cells and their progeny––a new approach to address unmet medical needs. This study has evaluated the effect of a silica-coated bioactive ceramic, namely HASi in comparison to hydroxyapatite (HA) on the adhesion, proliferation and osteogenic differentiation of goat bone marrow-derived mesenchymal stem cells in vitro in a prolonged culture of 28 days. The cellular activities were significantly enhanced on HASi signifying the role of silica to stimulate osteoblast cells. The fabrication of such a `cell-ceramic construct using autologous MSCs' is aimed for the transplantation to a large bone defect site in the goat femur model which still remains a formidable challenge in Orthopedic surgery.

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2008

Dr. Manitha B. Nair, Varma, H. K., and John, A., “Platelet-Rich Plasma and Fibrin Glue–Coated Bioactive Ceramics Enhance Growth and Differentiation of Goat Bone Marrow–Derived Stem Cells”, Tissue Engineering Part A, vol. 15, pp. 1619–1631, 2008.[Abstract]


New biotechnologies such as tissue engineering require functionally active cells within supportive matrices where the physical and chemical stimulus provided by the matrix is indispensable to determine the cellular behavior. This study has investigated the influence of platelet-rich plasma (PRP) and fibrin glue (FG) on the functional activity of goat bone marrow–derived mesenchymal stem cells (gBMSCs) that differentiated into the osteogenic lineage. To achieve this goal, PRP and FG were separately coated on bioactive ceramics like hydroxyapatite (HA) and silica-coated HA (HASi), on which gBMSCs were seeded and induced to differentiate into the osteogenic lineage for 28 days. The cells were then analyzed for viability (lactate dehydrogenase assay: acridine orange and ethidium bromide staining), morphology (scanning electron microscopy), proliferation (picogreen assay), cell cycle assay (propidium iodide staining), and differentiation (alkaline phosphatase [ALP] activity and real-time PCR analysis of ALP, osteocalcin, and osteopontin gene). It has been observed that PRP and FG have appreciably favored the viability, spreading, and proliferation of osteogenic-induced gBMSCs. The osteopontin and osteocalcin expression was significantly enhanced on PRP- and FG-coated HA and HASi, but PRP had effect on neither ALP expression nor ALP activity. The results of this study have depicted that FG-coated ceramics were better than PRP-coated and bare matrices. Among all, the excellent performance was shown by FG coated HASi, which may be attributed to the communal action of the stimulus emanated by Si in HASi and the temporary extracellular matrix provided by FG over HASi. Thus, we can conclude that PRP or FG in combination with bioactive ceramics could possibly enhance the functional activity of cells to a greater extent, promoting the hybrid composite as a promising candidate for bone tissue engineering applications.

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2006

Dr. Manitha B. Nair, HK, V., TV, K., SS, B., and A, J., “Cell Interaction Studies with Bioglass Coated Hydroxyapatite Porous Blocks”, Trends in Biomaterials and Artificial Organs , vol. 19, no. 2, pp. 108-114, 2006.

Publication Type: Conference Paper

Year of Publication Title

2016

Dr. Manitha B. Nair, “Relevance of Biopolymers & Nanocomposites in Tissue Engineering & Regenerative medicine”, in National Technology Day – CBPST, 2016.

2016

Dr. Manitha B. Nair, Shantikumar V. Nair, and A, A., “Gelatinous matrix with Silica coated Nanohydroxyapatite as a Biomimetic scaffold for Bone Tissue Engineering”, in NUS Joint International Conference on Biotechnology and Neuroscience - CUSBAN , 2016.

2015

S. Kuttappan, V, L. Sumitra, and Dr. Manitha B. Nair, “Development of composite scaffolds with genetically engineered stem cells expressing BMP2 for bone tissue engineering”, in Indo-Australian Conference on Biomaterials & Tissue Engineering – BiTERM , 2015.

2015

N. D, Vadukumpully, S., Nair, S., and Dr. Manitha B. Nair, “Evaluation of osteoinductive potential of Graphene oxide incorporated bioceramic composite scaffold for Bone tissue engineering”, in Indo-Australian Conference on Biomaterials & Tissue Engineering - BiTERM, 2015.

2015

Dr. Manitha B. Nair, Nair, A. A., Menon, D., and Nair, S., “Relevance of Fiber Reinforced Gelatin-HA Composite Scaffold For Bone Tissue Regeneration”, in Indo-Australian Conference on Biomaterials & Tissue Engineering – BiTERM , 2015.

2015

Dr. Manitha B. Nair, Krishnan, A. G., Jayaram, L., and Raja Biswas, “Ciprofloxacin loaded gelatin-hydroxyapatite scaffolds as a local drug delivery system for osteomyelitis treatment”, in Indo-Australian Conference on Biomaterials & Tissue Engineering – BiTERM , 2015.

2014

Dr. Manitha B. Nair, “Localized Drug Delivery in Bone tissue Engineering”, in National Seminar on Recent Advances in Biotechnology, St. Joseph’s College, Irinjalakuda, Kerala, 2014.

2014

A. A. Nair, V, M., Shantikumar V. Nair, and Dr. Manitha B. Nair, “Gelatin-nanohydroxyapatite scaffold with micro/nano fibers - A novel biomimetic bone substitute for Orthopaedic applications”, in 7th Bangalore India Nano, 2014.

2014

M. V, Dr. Manitha B. Nair, and Iyer, S., “Surgical alterations to enhance prosthetic outcome in maxillofacial rehabilitation”, in International Society for Maxillofacial Rehabilitation Conference China, 2014.

2013

B. Halima Shamaz, Nair, A. A., and Dr. Manitha B. Nair, “Characterization of 3D bony scaffold of NanoHA-gelatin with PLLA electrospun sheet”, in International Conference on Biotechnology for Innovative applications - Amrita Bioquest , 2013.

2013

E. Elizabeth, Nair, A. A., Menon, D., and Dr. Manitha B. Nair, “Titania Nanotubes loaded with zinc oxide nanoparticles for improved osseointegration and antibacterial activity”, in International Conference on Biotechnology for Innovative applications - Amrita Bioquest , 2013.

2013

A. A. Nair, Joseph, J., Koyakutty, M., Menon, D., Nair, S., and Dr. Manitha B. Nair, “Polymeric fiber containing nanohydroxyapatite based composite scaffolds for bone tissue engineering”, in International Conference on Biotechnology for Innovative applications - Amrita Bioquest , 2013.

2010

Rajesh Kannan Megalingam, Krishnan, V., Dr. Manitha B. Nair, Sarma, V., and Srikumar, R., “Serializing the data bus of the Sun OpenSPARC T1 microprocessor datapath for reduced power consumption”, in ICWET 2010 - International Conference and Workshop on Emerging Trends in Technology 2010, Conference Proceedings, Mumbai, Maharashtra, 2010, pp. 868-873.[Abstract]


Power consumption in processors have become a major issue in these days. This paper considers an efficient technique of serializing the datapath to reduce the power consumption as in [1]. We use the 64 bit datapath of Sun OpensSPARC T1 processor. This processor has four basic blocks for data manipulations which along with the register file and the bypass logic forms the datapath. Serialization is applied to all the four blocks which are the shift, multiply, divide, and Arithmetic and Logic (ALU) blocks. Power estimation and analysis are done for ALU and multiply blocks. We have introduced a module called serializer which is included as part of the bypass logic, to serialize the data path. Serializing can be brought about without much compromise in the speed but this paper emphasizes on the reduction in power consumption. The modified, bit serialized datapath of OpenSPARC T1 is implemented in Verilog HDL. Power analysis of original, parallel datapath and the modified, bit serialized datapath designs of OpenSPARC is done using Xilinx ISE 10.1 Power Analyzer. The results are discussed at the end of this paper. Copyright 2010 ACM. More »»

2010

Dr. Manitha B. Nair, Melethadathil, N., Dr. Bipin G. Nair, Dr. Shyam Diwakar, and Manjusha Nair, “Information processing via post-synaptic EPSP-spike complex and model-based predictions of induced changes during plasticity in cerebellar granular neuron”, in Proceedings of the 1st Amrita ACM-W Celebration of Women in Computing in India, A2CWiC'10, Coimbatore, 2010.[Abstract]


Understanding functional role of spike bursts in the brain circuits is vital in analyzing coding of sensory information. Information coding in neurons or brain cells happen as spikes or action potentials and excitatory post-synaptic potentials (EPSPs). Information transmission at the Mossy fiber- Granule cell synaptic relay is crucial to understand mechanisms of signal coding in the cerebellum. We analyzed spiking in granule cells via a detailed computational model and computed the spiking-potentiation contributing to signal recoding in granular layer. Plasticity is simulated in the granule cell model by changing the intrinsic excitability and release probability of the cells. Excitatory post synaptic potentials and spikes on varying Golgi cell (GoC) inhibition and Mossy fiber(MF) excitation were analyzed simultaneously with the effect of induced plasticity changes based on the timing and amplitude of the postsynaptic signals. It is found that a set of EPSPs reaching maximum threshold amplitude are converted to less number of high amplitude EPSPs or spikes. Exploring the EPSP-spike complex in granular neurons reveal possible mechanisms and quantification of information encoding in individual neurons of the cerebellar granular layer. Therefore, our study is potentially an important estimation of cerebellar function. © 2010 ACM.

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Publication Type: Patent

Year of Publication Title

2016

Dr. Manitha B. Nair, Dr. Deepthy Menon, and Shantikumar V. Nair, “Porous Composite Fibrous Scaffold for Bone Tissue Regeneration”, U.S. Patent 15/341,866 2016.

2015

Dr. Manitha B. Nair, Dr. Deepthy Menon, and Shantikumar V. Nair, “Porous Composite Fibrous Scaffold for Bone Tissue Regeneration”, U.S. Patent 5919/CHE/20152015.

Publication Type: Book Chapter

Year of Publication Title

2011

Dr. Manitha B. Nair, Sullivan, P. J., and Mortensen, E. K., “Bone Tissue Engineering Approaches and Challenges using Bioactive Ceramic Scaffolds”, Nova publishers, 2011, pp. 45-74.[Abstract]


Segmental bone defects resulting from trauma or pathological conditions represent formidable clinical challenges in orthopaedic surgery. Though current therapies include autografts and allografts or distraction osteogenesis, they are known for their inherent disadvantages like limited supply, increased morbidity, disease transmission potential and long term hospitalization respectively. In this context, tissue engineering becomes relevant for the treatment of large bone defects, where cells or growth factors are incorporated into a three-dimensional scaffold to mimic native tissue architecture and function in terms of osteoconduction, osteoinduction and osteointegration. Among the scaffolds, bioactive ceramics play an importance because of its similarity in chemical composition to bone. This review seeks to describe different tissue engineering approaches using bioactive ceramics towards bone regeneration in segmental bone defects. These include tissue-ingrowth (bioactive ceramics alone); cell transplantation (bioactive ceramics with mesenchymal stem cells) and signaling molecule (bioactive ceramics with growth factors).

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Dr. Manitha B. Nair,
Associate Professor
Laboratory for Tissue Engineering and Regenerative Medicine
Amrita Center for Nanosciences and Molecular Medicine
Amrita Institute of Medical Science, Ponekkara,
Kochi, Kerala 682 041, India

manithanair@aims.amrita.edu
+91-484-4001234 (Extn: 8704)