One step immobilization of glucose oxidase on TiO2 nanotubes towards glucose biosensing

Abstract

Biocatalysts of redox enzymes have fascinated escalating attention for development of electronic biomaterials and devices for industrial, clinical and environmental applications. Enzyme immobilization leads to more stable, repetitive and better activity. Including of immobilization substrate or materials; the different kinds of nanostructured TiO2 have often been used to immobilize enzymes on their surface for fabricating electrochemical biosensors, because of their unique physico-chemical properties constitute novel and interesting matrices. Glucose oxidase (GOx) is one of the typical enzymes which are being extensively used especially in glucose diagnosis. In this study, titanium dioxide nanotubes (TNT) were synthesized by electrochemical anodizing method and used as GOx immobilization substrate for glucose detection. The morphology, structure and electrochemical performance of TNT are characterized by field emission scanning electron microscope (FE-SEM), Energy-dispersive X-ray (EDX), X-ray Diffraction (XRD), Atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Our results show that the TNT electrode provides an excellent matrix for the GOx immobilization and exhibits a very low detection limit (8.5 µM), linearly range from 0.0 to 1.0 mM, with high stability and good reproducibility. These findings demonstrate a promising strategy to integrate enzymes and TNT, which could provide an analytical access to a large group of enzymes for bioelectrochemical applications.