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Facile pH-sensitive optical detection of pathogenic bacteria and cell imaging using multi-emissive nitrogen-doped carbon dots

Publication Type : Journal Article

Thematic Areas : Biotech

Publisher : Microchemical Journal

Source : Microchemical Journal, Volume 159, p.105324 (2020)

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Keywords : Carbon dots, Multicolor fluorimetry, Nitrogen doping, Pathogenic bacteria, pH-sensitive, Squamous epithelial cells

Campus : Amritapuri, Coimbatore

School : School of Biotechnology, School of Engineering

Center : Biosensor Research Lab, Biotechnology

Department : biotechnology, Sciences

Year : 2020

Abstract : Rapid detection of lethal pathogens is critical to abate the mortality rate of patients suffering from infectious diseases. Herein, we report a pH-sensitive detection of the pathogenic bacteria using multicolor emissive Nitrogen-doped Carbon Dots (NtCD) synthesized by a one-step hydrothermal method. The unique pH-sensitive interaction of NtCD with bacteria was best studied at pH 2. NtCD was competent to detect several pathogenic bacteria such as; Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis) and Proteus vulgaris (P. vulgaris). The fluorescence spectral investigations of NtCD revealed the excitation dependent emission property with a red-shift. It shows an intense photoluminescent (PL) emission at λex/λem = 340/435 nm. The calculated quantum yield of NtCD was 27.2%. It also possesses multicolor emission at different excitation wavelengths. TEM analysis displayed the uniform spherical morphology of NtCD particles with an average hydrodynamic diameter of 3.11 ± 0.75 nm. The zeta potential of NtCD was measured as −8.4 mV at pH 2. The interaction between NtCD and bacteria was explained on the basis of their zeta potential values. The PL emission response of NtCD tagged bacteria was investigated at λex = 340 nm. It was potentially tagging to both E. coli and S. aureus but with a better response towards E. coli cells. The human squamous epithelial cells (SEC) were deployed as a fitting substitute for achieving NtCD-mammalian cell imaging. Both NtCD tagged bacterial cells and SEC exhibited multicolor emission as well. Mechanistic implications of pH-dependent PL emission property of NtCD and its bacterial interaction were discussed extensively.

Cite this Research Publication : A. Pathak, Venugopal, P., Dr. Bipin G. Nair, Suneesh, P. Vasu, and Dr. Satheesh Babu T. G., “Facile pH-sensitive optical detection of pathogenic bacteria and cell imaging using multi-emissive nitrogen-doped carbon dots”, Microchemical Journal, vol. 159, p. 105324, 2020.

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