Paper-based microfluidic biofuel cell operating under glucose concentrations within physiological range

This work addresses the development of a compact paper-based enzymatic microfluidic glucose/O₂ fuel cell that can operate using a very limited sample volume (≈35 µl) and explores the energy generated by glucose at concentrations typically found in blood samples at physiological conditions (pH 7.4). Carbon paper electrodes combined with a paper sample absorption substrate all contained within a plastic microfluidic casing are used to construct the paper-based fuel cell. The anode catalysts consist of glucose dehydrogenase and [Os(4,4'-dimethoxy-2,2'-bipyridine)₂(poly-vinylimidazole)₁₀Cl]⁺ as mediator, while the cathode catalysts were bilirubin oxidase and [Os(2,2'-bipyridine)₂(poly-vinylimidazole)₁₀Cl]⁺ as mediator. The fuel cell delivered a linear power output response to glucose over the range of 2.5–30 mM, with power densities ranging from 20 to 90 µW cm⁻². The quantification of the available electrical power as well as the energy density extracted from small synthetic samples allows planning potential uses of this energy to power different sensors and analysis devices in a wide variety of in-vitro applications.