An O-2 Tolerant Polymer/Glucose Oxidase Based Bioanode as Basis for a Self-powered Glucose Sensor

The development of O-2 tolerant glucose sensors based on the highly active and robust enzyme glucose oxidase is still a major challenge because of the competition between the natural electron acceptor O-2 and free-diffusing or polymer-bound artificial electron acceptors. We report the fabrication of a glucose oxidase based bioanode that operates under ambient conditions. Combination of this bioanode with a bilirubin oxidase based biocathode enabled the fabrication of a glucose/O-2 powered biofuel cell as integrated power source for a self-powered device. Glucose oxidase at the anode was electrically wired via a low-potential redox polymer, i.e. a Toluidine Blue-modified poly(methacrylate) based polymer, that ensures a high open-circuit voltage of the biofuel cell but also catalytically reduces O-2 and hence requires a protection shield for measurements under ambient conditions. The sensing layer was deposited by means of potential pulse-assisted co-deposition of glucose oxidase within the redox polymer and was protected from O-2 by a newly proposed lactate oxidase/catalase based O-2 removal layer that was immobilized within a hydrophilic redox-silent polymer on top of the sensing layer. The protection layer was powered by lactate, a natural component in human blood. The biofuel cell exhibited an OCV of ca. 650mV and the power output was dependent on the glucose concentration without any interference from oxygen providing that lactate was available in the analyte solution.