Self-powered systems via enzymatic catalysis: Design and performance of glucose-based biobatteries

The escalating need for sustainable, biocompatible and subminiaturized natural power sources has driven noteworthy interest in glucose-based enzymatic biobatteries as alternatives to conventional electrochemical batteries. These systems harness biochemical reactions to convert the chemical energy of glucose, abundantly available in physiological fluids, directly into electrical energy under mild operating conditions, making them highly attractive for implantable medical devices, wearable electronics, biosensors, and self-powered bioelectronics. This review provides a critical overview of recent advances in glucose-based enzymatic biobatteries with particular emphasis on biological components, electrochemical architectures, catalytic strategies, and electron transfer mechanisms. Key anodic enzymes, including glucose oxidase and glucose dehydrogenase, as well as emerging nanozyme systems such as black phosphorus nanosheets, have been discussed in terms of catalytic efficiency, stability, and by-product management. Advances in mediated and direct electron transfer strategies enabled by nanostructured materials, conductive polymers, and three-dimensional porous electrodes are highlighted for their role in enhancing power density and operational durability. On the cathodic side, oxygen reduction catalysed by laccase and bilirubin oxidase is reviewed with particular attention to physiological compatibility and long-term stability. Hybrid and cascade enzymatic systems enable deep glucose oxidation with high energy densities, addressing challenges in enzyme lifetime, scalability, integration, and biomedical translation.