One-pot preparation of glucose biosensor based on polydopamine–graphene composite film modified enzyme electrode

A green, facile and low cost approach was developed to fabricate a glucose biosensor based on polydopamine–graphene hybrid film modified glucose oxidase enzyme electrode. Dopamine, graphene oxide and glucose oxidase were mixed and casted on Au electrode, and after electrochemical processing, polydopamine, glucose oxidase and graphene modified electrode was obtained. The as-synthesized enzyme electrodes were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and X-ray diffraction spectra. The biosensor showed the excellent amperometric biosensing performances, e.g., a high detection sensitivity (28.4 μA mM−1cm−2), a low limit of detection (0.1 μm), a short response periods (<4 s) and a low Michaelis–Menten constant (6.77 mM). This might be attributed to large surface-to-volume ratio and high conductivity of graphene, and good biocompatibility of polydopamine, which could enhance the enzyme absorption and promote direct electron transfer between redox enzymes and the surface of electrodes.