Direct electron transfer from glucose oxidase immobilized on an overoxidized polypyrrole film decorated with Au nanoparticles

Abstract

An overoxidized polypyrrole (OOPPy) film was electrodeposited on a glassy carbon electrode (GCE) and the modified electrode (GCE/OOPPy) was then decorated with Au nanoparticles (nanoAu). Glucose oxidase was immobilized on the surface of nanoAu decorated OOPPy modified GCE to fabricate a novel glucose biosensor (GCE/OOPPy-nanoAu/GOx). Cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were used to characterize the modified electrodes. A pair of well-defined redox peaks with a formal potential (E°′) of −0.449V and a peak to peak separation (ΔEp) of 28mV was observed for the direct electron transfer (DET) of the immobilized GOx. The electron transfer rate constant (ks) was calculated to be 10.3s−1. The fabricated glucose biosensor was employed for the determination of glucose in the concentration range between 1 and 8mM using cyclic voltammetry and amperometry. The results clearly demonstrate that nanoAu decorated OOPPy film is an excellent biocompatible scaffold for the immobilization of GOx and fabrication of a glucose biosensor.