Development of a membraneless single-enzyme biofuel cell powered by glucose

This work presents the development of a membraneless single-enzyme biofuel cell powered by glucose (GBFC). The GBFC biocathode is based on a graphite rod electrode (GRE) coated with a layer of Prussian blue (PB) nanoparticles entrapped into poly(pyrrole-2-carboxylic acid) (PPCA) shell, an additional layer of PPCA, and covalently to polymer linked glucose oxidase (GOx). The bioanode is based on GRE modified with a nanobiocomposite composed of poly(1,10-phenanthroline-5,6-dione), gold nanoparticles entrapped in a PPCA shell, and GOx linked by an amide bond to polymer. The operation of the developed single-enzyme GBFC is based on GOx-catalysed oxidation of glucose on both the bioanode and biocathode and reduction of H₂O₂ electrocatalysed by PB on the biocathode. The GBFC operated in O₂-saturated buffer medium pH 6.0 containing glucose. An open-circuit voltage (OCV) of 646 mV, a maximum power density of 10.94 μW/cm² and a current density of 60.52 μA/cm² at 40 mM glucose were determined. OCV and current density were directly proportional to glucose concentration in 0.01-10.00 mM and 0.05-124.00 mM concentration ranges, respectively. In addition, GBFC had good operational stability and retained more than 90% of the initial OCV after 36 days.