Direct electrochemistry of glucose oxidase based on Nafion-Graphene-GOD modified gold electrode and application to glucose detection

• Graphene with crumpled and wrinkled sheet structure was prepared by the chemical reduction method.
• Graphene and glucose oxidase was immobilized on gold electrode by physical adsorption.
• Direct electron transfer was achieved efficiently with the aid of graphene.
• Glucose biosensor based on nafion protected graphene exhibited wide linear range and high sensitivity.

Direct electrochemistry of glucose oxidase (GOD) based on Nafion-Graphene-GOD modified gold disk electrode (GE) was studied in this work. Immobilized GOD on graphene protected by nafion film exhibited good bioactivity, stability and apparent electron transfer rate constant (ks) 1.96 s−1. Cyclic voltammetric results of the electrode showed a pair of well-defined and quasi-reversible redox peaks, suggesting the direct electron transfer between GOD and the electrode surface. The proposed biosensor exhibited a wider linear response to glucose concentrations between 2 and 14 mM with a detection limit of 0.04 mM and a higher sensitivity (21.9 μA mM−1 cm−2) compared with other nanostructured supports.