An enzyme-based glucose/O-2 biofuel cell was constructed within a microfluidic channel to study the influence of electrode configuration and fluidic channel height on cell performance. The cell was composed of a bilirubin oxidase (BOD)-adsorbed O-2 cathode and a glucose anode prepared by co-immobilization of glucose dehydrogenase (GDH), diaphorase (Dp) and VK3-pendant poly-L-lysine. The consumption of O-2 at the upstream cathode protected the downstream anode from interfering O-2 molecules, and consequently improved the cell performance (maximum cell current) ca. 10% for the present cell. The cell performance was also affected by the channel height. The output current and power of a 0.1 mm-height cell was significantly less than those of a 1 mm-height cell because of the depletion of O-2, as determined by the shape of the E-I curve at the cathode. On the other hand, the volume density of current and power was several times higher for the narrower cell. (C) 2007 Elsevier B.V. All rights reserved.