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

Abstract

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 coupled with an oxygen-reducing bilirubin oxidase on gold nanoparticle dispersed on gold electrode as a biocathode to provide a membraneless fully enzymatic fuel cell. A maximum power density of 275 μW cm(-2) is obtained in 5 mM glucose in PBS, the highest to date under these conditions, providing sufficient power to enable wireless transmission of a signal to a data logger. When tested in whole human blood and unstimulated human saliva maximum power densities of 73 and 6 μW cm(-2) are obtained for the same fuel cell configuration, respectively.

An enzymatic glucose/O2 biofuel cell operating in human blood

“…In presence of 5.4 mM glucose, Ó Conghaile et al reached 73 77 mW cm À 2 at 0.3 V (Conghaile et al, 2016). At 4.6 mM glucose concentration we could reach a power density 21 times higher at 0.47 V (59 mW cm À 2 vs. 2.8 mW cm À 2 ) than what was reported by Nien et al (Wang et al, 2012).…”

“…(Milton et al, 2015) The maximum power densities were respectively 145.7 mW cm À 2 at 0.35 V in PBS and 68.1 mW cm À 2 at 0.38 V in blood, indicating the good selectivity of our system since only ∼50% of power density is lost in blood. In a recent study, it was shown that the power density in blood could be a quarter of that observed in PBS (Conghaile et al, 2016).…”

Rectangular flake-like mesoporous NiCo2O4 as enzyme mimic for glucose biosensing and biofuel cell

“…Moreover, as shown in Table 2, the cell properties of GBFC I are superior to those of GBFC II. These findings reveal that meso-NiCo 2 O 4 displays better catalytic properties to glucose than previous reports including the non-and enzyme fuel cells [48,49]. In short, the meso-NiCo 2 O 4 with large specific surface area is a promising anode material for the practical fabrication of GBFC.…”

Power Generation versus Conventional Potentiostatic Operation of Prussian Blue Based (Bio)Sensors

“…So, the only feasible analytical application of (bio)sensing without external power supply is the amperometry in short‐circuit regime. In such a regime the operation of the working electrode generally occurs far from its optimal potential due to large potential difference between the electrodes destined to maximize power output . To overcome this disadvantage of the conventional self‐powering approach, we suggest short‐circuiting the electrodes with the lowest potential difference.…”