An enzymatic glucose/O2 biofuel cell: Preparation, characterization and performance in serum

This study demonstrates a new kind of single-walled carbon nanotubes (SWNT)-based compartment-less glucose/O2 biofuel cell (BFC) with glucose dehydrogenase (GDH) and bilirubin oxidase (BOD) as the anodic and cathodic biocatalysts, respectively, and with poly(brilliant creysl blue) (BCB) adsorbed onto SWNT nanocomposite as the electrocatalyst for the oxidation of NADH. The prepared GDH-polyBCB-SWNT bioanode exhibits an excellent electrocatalytic activity toward the oxidation of glucose biofuel; in 0.10 M phosphate buffer containing 20 mM NAD+ and 100 mM glucose, the oxidation of glucose commences at −0.25 V and the current reaches its maximum of 310 μA/cm2 at −0.05 V vs. Ag/AgCl. At the BOD-SWNT biocathode, a high potential output is achieved for the reduction of O2 due to the direct electron transfer property of BOD at the SWNTs. In 0.10 M phosphate buffer, the electrocatalytic reduction of O2 is observed at a high potential of 0.53 V vs. Ag/AgCl with an electrocatalytic current plateau of ca. 28 μA/cm2 at 0.45 V under ambient air and ca. 102 μA/cm2 under O2-saturated atmosphere. In 0.10 M phosphate buffer containing 10 mM NAD+ and 40 mM glucose under O2-saturated atmosphere, the power density of the assembled SWNT-based glucose/O2 BFC reaches 53.9 μW/cm2 at 0.50 V. The performance and the stability of the glucose/O2 BFC are also evaluated in serum. This study could offer a new route to the development of new kinds of enzymatic BFCs with a high performance and provide useful information on future studies on the enzymatic BFCs as in vivo power sources.