Polyaniline-CdS Quantum Dots Composite for Mediator Free Biosensing
- *Corresponding Author:
- Hemant Dhyani
School of Physical Sciences
Jawaharlal Nehru University
New Delhi-110067, India
E-mail: [email protected]
Received Date: October 10, 2011; Accepted Date: December 12, 2011; Published Date: December 16, 2011
Citation: Dhyani H, Dhand C, Malhotra BD, Sen P (2011) Polyaniline-CdS Quantum Dots Composite for Mediator Free Biosensing. J Biosens Bioelectron 3:112. doi: 10.4172/2155-6210.1000112
Copyright: © 2011 Dhyani H, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
A novel route has been introduced to fabricate the composite of polyaniline (PANI) and cadmium sulphide quantum dots (CdS-QD) using electrochemical polymerization technique for mediator free biosensing. The synthesis process involves in situ formation of CdS quantum dots that provide template for eletro-polymerization of aniline resulting in nanostructured PANI-(CdS-QD) film deposition on the indium-tin-oxide (ITO) coated glass plate. Transmission electron microscopy and scanning electron microscopy have been used to reveal the formation of CdS-QD and morphological changes involved during incorporation of CdS in PANI matrix and while immobilization of cholesterol oxidase (ChOx). The UV–visible and FT-IR investigations show the formation of PANI-(CdS-QD) composite at the molecular level. This matrix has been utilized for the covalent immobilization of cholesterol oxidase to explore its application for cholesterol sensing. The results of the CV and EIS studies indicate enhanced electrochemical and charge transfer behaviour of the composite. The response studies, carried out using CV technique, reveal this ChOx/ PANI-(CdS-QD)/ITO bioelectrode to detect cholesterol in the concentration range of 50 to 500 mgdL -1 with good detection limit (47.8 mgdL -1 ) and low app m K value (0.82 mM).