Mishra, Sujeet K. and Srivastava, Avanish K. and Kumar, Devendra and Biradar, Ashok M. and Rajesh, - (2013) Microstructural and electrochemical impedance characterization of bio-functionalized ultrafine ZnS nanocrystals-reduced graphene oxide hybrid for immunosensor applications. Nanoscale, 5 (21). pp. 10494-10503. ISSN 2040-3364

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Abstract

We report a mercaptopropionic acid capped ZnS nanocrystals decorated reduced graphene oxide (RGO) hybrid film on a silane modified indium-tin-oxide glass plate, as a bioelectrode for the quantitative detection of human cardiac myoglobin (Ag-cMb). The ZnS nanocrystals were anchored over electrochemically reduced GO sheets through a cross linker, 1-pyrenemethylamine hydrochloride, by carbodiimide reaction and have been characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The transmission electron microscopic characterization of the ZnS-RGO hybrid shows the uniform distribution of ultra-fine nanoparticles of ZnS in nano-sheets of GO throughout the material. The protein antibody, Ab-cMb, was covalently linked to ZnS-RGO nanocomposite hybrid for the fabrication of the bioelectrode. A detailed electrochemical immunosensing study has been carried out on the bioelectrode towards the detection of target Ag-cMb. The optimal fitted equivalent circuit model that matches the impedance response has been studied to delineate the biocompatibility, sensitivity and selectivity of the bioelectrode. The bioelectrode exhibited a linear electrochemical impedance response to Ag-cMb in a range of 10 ng to 1 mu g mL(-1) in PBS (pH 7.4) with a sensitivity of 177.56 Omega cm(2) per decade. The combined synergistic effects of the high surface-to-volume ratio of ZnS(MPA) nanocrystals and conducting RGO has provided a dominant charge transfer characteristic (R-et) at the lower frequency region of < 10 Hz showing a good biocompatibility and enhanced impedance sensitivity towards target Ag-cMb. The impedance response sensitivity of the ZnS-RGO hybrid bioelectrode towards Ag-cMb has been found to be about 2.5 fold higher than that of a bare RGO modified bioelectrode.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Royal Society of Chemistry.
Subjects:	Chemistry Materials Science Applied Physics/Condensed Matter Nanoscience/ Nanotechnology
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	09 Jul 2020 10:32
Last Modified:	09 Jul 2020 10:32
URI:	http://npl.csircentral.net/id/eprint/3123

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