Covalent immobilization of cholesterol esterase and cholesterol oxidase on polyaniline films for application to cholesterol biosensor

摘要

Cholesterol esterase(ChEt)and cholesterol oxidase(ChOx)have been covalently immobilized on electrochemically prepared polyaniline(RANI)films.These PANI/ChEt/ChOx enzyme films have been characterized using UV-visible,Fourier transform infrared(FTIR)spectroscopy and scanning electron microscopy(SEM).Electrochemical behavior of these films has been studied using cyclic voltammetry(CV)and amperometric techniques,respectively.The PANI/ChEt/ChOx enzyme films show broad oxidation peak from 0.2 to 0.5 V.These PANI/ChEt/ChOx biosensing electrodes have a response time of about 40 s,linearity from 50 to 500 mg/dl of cholesterol oleate concentration.These PANI/ChEt/ChOx films are thermally stable up to 46 deg C.This polyaniline based cholesterol biosensor has optimum pH in the range of 6.5-7.5,sensitivity as 7.5 X 10~(-4)nA/mg dl and a lifetime of about 6 weeks.