Microbial electricity generation via microfluidic flow control

Next generation battery technology is rapidly evolving to meet the demand for higher power densities and smaller footprints through novel catalysts and battery architecture. We present a µ‐scale, biological fuel cell which utilizes microbial electricity generation enabled by microfluidic flow control to produce power. The new fuel cell, the smallest of its kind, with a total volume of 0.3 µL, produces scalable and controllable electrical energy from organic matter which is sustained through microbial respiration and laminar flow separation of the electrolytes. Electrical currents are dependent on specific biofilm formation on the anode, the concentration of electron donor, and a diffusion‐limited flow regime. A maximum current density of 18.40 ± 3.48 mA m−2 (92 ± 17 A m−3) was produced by Geobacter sulfurreducens, and 25.42 mA m−2 (127 A m−3) by Shewanella oneidensis. The µ‐scale biological fuel cell introduces the necessary small size and fuel flexibility for applications in vivo and in situ sensors which may be remotely deployed and self‐powered. Biotechnol. Bioeng. 2011;108:2061–2069. © 2011 Wiley Periodicals, Inc.