Direct electrochemistry of GOD on nitrogen-doped porous carbon and its biosensing

Nitrogen-doped porous carbon (N-DPC) was prepared via a simple and effective method and was characterized by X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, N₂ adsorption–desorption isotherms and scanning electron microscopy. The results showed that the N-DPC with two type reticular porosities in an average diameter of 10–100 nm has a large specific surface area, which is favorable to immobilize the redox proteins for constructing biosensors. Direct electrochemistry of glucose oxidase (GOD) on the N-DPC-modified electrode was investigated. UV–vis spectroscopy showed that GOD retained its catalytic activity in the N-DPC film. Electrochemical results indicated that the modified electrode exhibited effective direct electron transfer. It demonstrated that such N-DPC could provide a good matrix for direct electrochemistry of enzymes. A novel biosensor was developed by entrapping GOD in the N-DPC-modified electrode for glucose detection and showed a stable, rapid, and reproducible electrocatalytic response, a high sensitivity, a wide linear range and a low detection limit. Moreover, the biosensor can be applied in practical analysis and exhibit good reproducibility and long-term stability.