A novel glucose biosensor based on direct electrochemistry of glucose oxidase incorporated in biomediated gold nanoparticles–carbon nanotubes composite film

A novel glucose biosensor based on biomediated gold nanoparticles (AuNPs)–glucose oxidase (GOD)–carbon nanotubes–polyvinyl alcohol biocomposite film was fabricated for the first time. Direct electrochemistry of GOD in the film was obtained, proved by one pair of well-defined, quasi-reversible redox peaks with the formal potential of −0.504 V in pH 7.0 phosphate buffer solution at the scan rate of 100 mV s−1. And the electron transfer rate constant of the direct electron communication between GOD and the electrode was calculated to be 2.2 s−1. The biomediated AuNPs play an important role in facilitating the electron exchange between the electroactive center of GOD and the electrode. Furthermore, the fabricated electrode displayed a linear amperometric response in the glucose concentration range from 0.5 to 8.0 mM with a relatively high sensitivity of 16.6 μA mM−1 cm−2. Therefore, the AuNPs based biosensor described here provides a different mode to design electrochemical devices.