Glucose oxidation by osmium redox polymer mediated enzyme electrodes operating at low potential and in oxygen, for application to enzymatic fuel cells. (10th November 2015)

• Record Type: Journal Article
• Authors: Osadebe, Isioma; Conghaile, Peter Ó; Kavanagh, Paul; Leech, Dónal
• Is Part Of: Electrochimica acta. Volume 182(2015)
• Page Start: 320
• Page End: 326
• Publication Date: 2015-11-10
• Subjects: Redox polymer -- enzymatic fuel cell -- glucose -- glucose dehydrogenase; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.09.088
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Graphite electrodes modified with a redox polymer, [Os(4, 4′- dimethoxy-2, 2′-bipyridine)2 (polyvinyl imidazole)10 Cl]Cl (E°′ = −0.02 V vs Ag/AgCl), crosslinked with glucose oxidising enzymes and various amounts of multi-walled carbon nanotubes are investigated for current generation in the presence of glucose in physiological buffer solutions. Enzyme electrodes based on glucose oxidase and FAD-dependent glucose dehydrogenase are compared in the presence and absence of oxygen. The highest glucose oxidation currents are produced from enzyme electrodes containing 68% w/w multi-walled carbon nanotubes in the deposition matrix. The FAD-dependent glucose dehydrogenase and glucose oxidase enzyme electrodes provide similar current density of ∼0.8 mA cm −2 in de-oxygenated 50 mM phosphate-buffered saline at 37 °C containing 5 mM glucose concentration. Current densities under the same conditions, but in the presence of oxygen are 0.50 mA cm −2 and 0.27 mA cm −2, for glucose dehydrogenase and glucose oxidase enzyme electrodes, respectively, with decreased currents a result of oxygen reduction by the redox polymer in both cases, and oxygen acting as a co-substrate for the glucose oxidase-based electrodes. Application of the anodes in membrane-less enzymatic fuel cells is demonstrated by connection to cathodes prepared by co-immobilisation of [Os(2, 2′-bipyridine)2 (polyvinyl imidazole)10 Cl]Cl redox polymer, Myrothecium verrucaria bilirubin oxidase and multi-walled carbon nanotubes on graphite electrodes. Power densities of up to 270 μW cm −2 are achieved, showing promise for in vivo or ex vivo power generation under these conditions.