Fully Enzymatic Membraneless Glucose|Oxygen Fuel Cell That Provides 0.275 mA cm–2 in 5 mM Glucose, Operates in Human Physiological Solutions, and Powers Transmission of Sensing Data

Coimmobilization of pyranose dehydrogenase as an enzyme catalyst, osmium redox polymers [Os(4,4′-dimethoxy-2,2′-bipyridine)2(poly(vinylimidazole))10Cl]+ or [Os(4,4′-dimethyl-2,2′-bipyridine)2(poly(vinylimidazole))10Cl]+ as mediators, and carbon nanotube conductive scaffolds in films on graphite electrodes provides enzyme electrodes for glucose oxidation. The recombinant enzyme and a deglycosylated form, both expressed in Pichia pastoris, are investigated and compared as biocatalysts for glucose oxidation using flow injection amperometry and voltammetry. In the presence of 5 mM glucose in phosphate-buffered saline (PBS) (50 mM phosphate buffer solution, pH 7.4, with 150 mM NaCl), higher glucose oxidation current densities, 0.41 mA cm–2, are obtained from enzyme electrodes containing the deglycosylated form of the enzyme. The optimized glucose-oxidizing anode, prepared using deglycosylated enzyme coimmobilized with [Os(4,4′-dimethyl-2,2′-bipyridine)2(poly(vinylimidazole))10Cl]+ and carbon nanotubes, was cou...