A Glucose Biosensor based on Horseradish Peroxidase and Glucose Oxidase Co-entrapped in Carbon Nanotubes Modified Electrode

In this work, glucose oxidase (GOD) and horseradish peroxidase (HRP) were co-assembled onto carbon nanotubes (CNTs) modified glassy carbon electrode (GCE) to prepare a novel bi-enzyme electrode. The electrocatalytic performance and electron transfer of GCE/CNTs/GOD-HRP were explored by Cyclic voltammetry (CV). The UV-vis absorption spectroscopy showed that the HRP and GOD formed a protein complex and their structure was well kept. The CVs results also showed that the CNTs enhanced the immobilization of GOD-HRP and facilitated the electron transfer. GOD's biological activity was well kept due to the biocompatible microenvironment provided by the surrounding HRP. The effects of electrolyte pH and scan rate on the catalytic performance of the bi-enzyme were investigated. The GCE/CNTs/GOD-HRP electrode is used to construct an electrochemical glucose sensor. The sensor showed satisfactory results with a wide linear range from 0.022 to 7.0 mM, a high sensitivity of 5.14 mu A mM(-1) cm(-2), and a low detection limit of 7 mu M. The as-prepared sensor also display advantages of good selectivity, high repeatability and reproducibility, and relatively high stability.