Zinc oxide nanoparticles-chitosan composite film for cholesterol biosensor Original Research Article

Zinc oxide nanoparticles (NanoZnO) uniformly dispersed in chitosan (CHIT) have been used to fabricate a hybrid nanocomposite film onto indium-tin-oxide (ITO) glass plate. Cholesterol oxidase (ChOx) has been immobilized onto this NanoZnO–CHIT composite film using physiosorption technique. Both NanoZnO-CHIT/ITO electrode and ChOx/NanoZnO-CHIT/ITO bioelectrode have been characterized using Fourier transform-infrared (FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) techniques, respectively. The ChOx/NanoZnO-CHIT/ITO bioelectrode exhibits linearity from 5 to 300 mg dl−1 of cholesterol with detection limit as 5 mg dl−1, sensitivity as 1.41 × 10−4 A mg dl−1 and the value of Michaelis–Menten constant (Km) as 8.63 mg dl−1. This cholesterol biosensor can be used to estimate cholesterol in serum samples.