Redox Capacitor to Establish Bio‐Device Redox‐Connectivity

Electronic devices process information and transduce energy with electrons, while biology performs such operations with ions and chemicals. To establish bio‐device connectivity, we fabricate a redox‐capacitor film from a polysaccharide (i.e., chitosan) and a redox‐active catechol. We report that these films are rapidly and repeatedly charged and discharged electrochemically via a redox‐cycling mechanism in which mediators shuttle electrons between the electrode and film (capacitance ≈ 40 F/g or 2.9 mF/cm²). Further, charging and discharging can be executed under bio‐relevant conditions. Enzymatic‐charging is achieved by electron‐transfer from glucose to the film via an NADPH‐mediated redox‐cycling mechanism. Discharging occurs by electron‐donation to O₂ to generate H₂O₂ that serves as substrate for peroxidase‐mediated biochemical reactions. Thus, these films offer the capability of inter‐converting electrochemical and biochemical inputs/outputs. Among potential applications, we anticipate that catechol–chitosan redox‐capacitor films could serve as circuit elements for molecular logic operations or for transducing bio‐based chemical energy into electricity.