ANYL 145

Chitosan (CHIT) films have been prepared onto Indium-Tin-Oxide (ITO) substrate, using nanostructure ZnO dispersion. The cholesterol oxidase (ChOx) was immobilized onto CHIT-ZnO/ITO electrode without mediator. The fabricated CHIT, CHIT/ZnO nanocomposite and ChOx immobilized onto CHIT/ZnO films have been characterized using Fourier Transform-Infrared (FT-IR), X-Ray diffraction (XRD), Cyclic Voltammogram (CV), Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS) techniques. ChOx/CHIT/ZnO/ITO bioelectrode exhibits linearity from 5 to 300 mg/dl of cholesterol detection limit as 5 mg/dl with sensitivity as 1.41 ×10-4 A mg/dl. The value of the Michaelis-Menten constant (Km) calculated from cholesterol response measurement was found to be 8.63 mg/dl for ChOx/CHIT/ZnO/ITO bioelectrode. The biosensor was used to determine cholesterol in serum samples with satisfactory results.

Keywords: Biosensor; Chitosan; Electroactive biopolymer; ChOx; ZnO nanoparticles