Enzyme-based biofuel cells for biosensors and in vivo power supply

Biofuel cells (BFCs) are energy conversion devices using biocatalysts to convert biochemical energy into electric energy. According to different catalysts, they can be divided into microbial fuel cells (MBFCs), enzyme biofuel cells (EBFCs), organelle biofuel cells (OBFCs), and photocatalytic fuel cells (PFCs). Compared with traditional fuel cells, EBFCs can provide sustainable energy under mild conditions such as physiological temperatures and near-neutral media, which have attracted extensive attention in the field of medical implants, drug pumps, biosensors and other devices. Enzyme load capacity and electron transfer rate are the key issues affecting the performance of EBFCs. Immobilization of enzyme on conductive materials with high specific surface area and good biocompatibility can effectively solve the bottleneck problems of EBFCs in actual applications such as low power density and short service life. This paper summarizes common biological enzymes of EBFCs and their immobilization methods, and emphasizes the breakthrough of nanomaterials, such as carbon nanomaterials, metal nanomaterials and composites in the fields of EBFCs. In addition, the application, challenges, and prospects of the EBFCs in the future development direction are also proposed.