Development of a cholesterol biosensor based on polyaniline-Ag nanocomposites

International Conference and Exhibition on Biosensors & Bioelectronics

May 14-16, 2012 Embassy Suites Las Vegas, USA

Ravendra P.S. Chauhan, R.K. Basniwal, Shadab Parvez and V.K. Jain

Posters: J Biosens Bioelectron

Abstract :

In the present study, chronoamperometry was employed to prepare polyaniline- p- toluene sulphonic acid- silver (PANI-pTSAAg) nanocomposite film on indium tin oxide (ITO) coated glass plate for covalent immobilization of cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) via N-ethyl-N?-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to fabricate a cholesterol bioelectrode (ChEt-ChOx/ PANI?pTSA-Ag /ITO). The scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemical techniques were employed for characterizing PANI?pTSA-Ag /ITO electrode and ChEt-ChOx/ PANI?pTSA-Ag /ITO bioelectrode. We observed the high sensitivity of 36.3μA/ mg/dl with a fast response time of 10 seconds in the range of 20 to 400 mg/dl for the bioelectrode. The linear regression analysis of bioelectrode revealed standard deviation and correlation coefficient of 11.6 μA and 0.992, respectively. The low value of Michaelis?Menten constant (Km) estimated as 6.99mg/dl (0.107mM) indicates high affinity of cholesterol esterase and cholesterol oxidase enzymes to cholesterol. We observed that the ChEt-ChOx/ PANI?pTSA-Ag /ITO bioelectrode exhibits uniform activity for 50 days under refrigerated conditions. Attempts have been made to utilize this electrode for estimation of total cholesterol in blood serum samples.