Direct electron transfer at a glucose oxidase-chitosan-modified Vulcan carbon paste electrode for electrochemical biosensing of glucose.

This article describes the investigation of direct electron transfer (DET) between glucose oxidase (GOD) and the electrode materials in an enzyme-catalyzed reaction for the development of improved bioelectrocatalytic system. The GOD pedestal electrochemical reaction takes place by means of DET in a tailored Vulcan carbon paste electrode surfaces with GOD and chitosan (CS), allowing efficient electron transfer between the electrode and enzyme. The key understanding of the stability, biocatalytic activity, selectivity, and redox properties of these enzyme-based glucose biosensors is studied without using any reagents, and the properties are characterized using electrochemical techniques like cyclic voltammogram, amperometry, and electrochemical impedance spectroscopy. Furthermore, the interaction between the enzyme and the electrode surface is studied using ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy. The present glucose biosensor exhibited better linearity, limit of detection (LOD = 0.37 ± 0.02 mol/L) and a Michaelis-Menten constant of 0.40 ± 0.01 mol/L. The proposed enzyme electrode exhibited excellent sensitivity, selectivity, reproducibility, and stability. This provides a simple "reagent-less" approach and efficient platform for the direct electrochemistry of GOD and developing novel bioelectrocatalytic systems.