Self-Powered Biosensor Driven by a Hybrid Biofuel Cell with CuCoP-Polyoxometallate Composite as Both Cathode Catalyst and Sensing Interface.

Abnormal concentrations of hydrogen peroxide (H2O2) are toxic to living cells and may induce a number of diseases. Herein, a self-powered miniaturized biosensor (SPB) based on an enzyme biofuel cell is constructed to monitor H2O2. This SPB significantly minimized the use of bioenzymes that often experience instability and lead to the high cost of biosensors. More specifically, a composite of polydopamine (PDA)-gold nanoparticles (AuNPs) is prepared as an anodic catalyst scaffold to immobilize glucose oxidase to efficiently catalyze the oxidation of glucose (fuel) due to its excellent biocompatibility and electrical conductivity. Upon the incorporation of CuCoP with a polyoxometalate H3PW12O40 (PW12), a nanoenzyme of CuCoP-PW12 composite is realized as a non-biological cathodic catalyst to replace the conventional cathode enzymes for the reduction of H2O2. The abundant catalytic active sites on CuCoP-PW12 and high electron transfer rate of PW12 result in a high catalytic activity toward H2O2 reduction at the cathode. Owing to a good synergy between the bioanode and abiotic-cathode, the prepared SPB exhibits two linear ranges (2-20 and 20-50 µm) and a low detection limit (0.0589 µm) toward H2O2 detection. Upon the use of H2O2 as a model analyte, this work demonstrates that SPB can be effectively applied in biomedical sensing.