Bacterial cellulose-carbon nanotube composite as a biocompatible electrode for the direct electron transfer of glucose oxidase

Background: Bacterial cellulose (BC)-based materials have many potential applications in the biomedical field because of their inherent biocompatibility. Carbon nanotubes (CNTs) have been used as electrode materials owing to their high electrical conductivity. In this study, BC-CNT composite electrodes were prepared simply by directly filtering CNTs through BC hydrogel and vacuum drying the BC hydrogel containing the CNTs. Glucose oxidase (GOx) was immobilized on BC-CNT composite electrodes. Results: Cyclic voltammograms revealed that the BC-CNT-GOx electrodes had a pair of well-defined peaks. The formal redox potential peak was -496 mV (vs. Ag/AgCl), which agreed well with that of FAD/FADH₂. This result clearly indicates that direct electron transfer occurred between GOx and the BC-CNT composite electrode. In addition, the GOx immobilized on the electrode retained its catalytic ability to oxidize glucose. Conclusion: Conductive BC-CNT composite films form a good biocompatible electrode for the direct electron transfer of glucose oxidase. They have many potential applications in the biomedical field such as biosensors, biofuel cells, and bioelectronic devices.