Covalent immobilization of cholesterol esterase and cholesterol oxidase on polyaniline films for application to cholesterol biosensor [An article from: Analytica Chimica Acta]

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Description:
Cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) have been covalently immobilized on electrochemically prepared polyaniline (PANI) 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 0.5V. These PANI/ChEt/ChOx biosensing electrodes have a response time of about 40s, linearity from 50 to 500mg/dl of cholesterol oleate concentration. These PANI/ChEt/ChOx films are thermally stable up to 46^oC. This polyaniline based cholesterol biosensor has optimum pH in the range of 6.5-7.5, sensitivity as 7.5x10^-^4nA/mgdl and a lifetime of about 6 weeks.