Direct Electrochemistry of Glucose Oxidase Immobilized on Chitosan‐gold Nanoparticle Composite Film on Glassy Carbon Electrodes and Its Biosensing Application

Abstract

AbstractThe direct electrochemistry of glucose oxidase (GOx) immobilized on a composite matrix based on chitosan (CHIT) and Au nanoparticles (Au NP) underlying on a glassy carbon electrode was achieved. The cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the modified electrode. In deaerated buffer solutions, the cyclic voltammetry of the composite films of GOx‐Au NP‐CHIT showed a pair of well‐behaved redox peaks that were assigned to the redox reaction of GOx, confirming the effective immobilization of GOx on the composite film. The electron transfer rate constant was estimated to be 15.6 s−1, indicating a high electron transfer between the GOx redox center and electrode. The combination of CHIT and Au NP also promoted the stability of GOx in the composite film and retained its bioactivity, which might have the potential application to glucose determination. The calculated apparent Michaelis‐Menten constant was 10.1 mmol·L−1. Furthermore, the proposed biosensor could be used for the determination of glucose in human plasma samples.