Amperometric Detection of Glucose Using a Modified Nitrogen-Doped Nanocrystalline Diamond Electrode

A glucose biosensor has been fabricated based on a modified nitrogen-doped nanocrystalline diamond (NCD) electrode. NCD films were synthesized by the microwave plasma enhanced chemical vapor deposition (MPECVD) method with nitrogen doping to make the film conductive. NCD films were then exposed to hydrogen plasma to obtain hydrogenated surface for further surface modification. Carboxyl functional groups have been employed to functionalize the NCD electrode and to immobilize the glucose oxidase (GOX) enzyme. Cyclic voltammograms (CV) were performed to evaluate the responses of the NCD electrode with different glucose concentrations. A linear calibration curve of glucose sensing has been obtained over the concentration range up to 13 mM in phosphate buffer solution. Temperature dependence and long term stability of the sensor have also been studied.