A mediator-free self-powered glucose biosensor based on a hybrid glucose/MnO₂ enzymatic biofuel cell

Self-powered glucose biosensor (SPGB) is of great interest due to the advantages including single configuration, good stability and particularly no need of external power sources. Herein, a mediator-free SPGB with high sensitivity and good selectivity is constructed based on a hybrid enzymatic biofuel cell (EBFC) composed of a glucose oxidase/cobalt phthalocyanine/1-pyrenebutyric acid/ buckypaper (GOD/CoPc/PBA/BP) bioanode and a MnO₂/PBA/BP capacitive cathode. The efficient electron transfer from GOD to electrodes is achieved successfully through the anode oxidation of hydrogen peroxide (H₂O₂), one nature product of glucose oxidation catalyzed by GOD, thus avoiding the potential drawbacks posed by the use of redox mediators. CoPc servers as an efficient catalyst to lower the anode potential required by the reaction of H₂O₂ to 0.17 V. The MnO₂/PBA/BP capacitive cathode is utilized because it can not only provide a high discharge potential and adequate capacitance to match the bioanode well, but also exhibit no potential interference to the anodic reaction. The concentration of glucose can be detected simply by measuring the output of the SPGB and a wide linear detection range from 0.5 to 8 mM has been obtained with high sensitivities of 48.66 and 32.12 μA·cm^-2·mM^-1 with and without stirring, respectively. The recoveries of glucose in grape juice and human serum are in the range from 99.5% to 101.2% with the relative standard deviation (RSD) less than 8%, indicating the good promise of the SPGB in sensing glucose in real samples.