Recently microbial fuel cells (MFCs) have attracted increasing interests in both environmental and energy fields. Among the various MFC configurations, miniature microbial fuel cell (mini-MFC) has a great potential for the application in medical, communication and other areas because of its miniature volume and high output power density.
The group of Prof. Yu from University of Science and Technology of China had fabricated a 25-μL single-chamber mini-MFC using the photolithography technique. A biofilm of Shewanella oneidensis MR-1 was formed on the surface of gold electrode in the micro-liter-scale MFCs.

　　　
(A) Schematic of the mini-MFC assembly; (B) image of the anodic layer consisting of glass substrate, gold electrode and PMMA anodic well; (C) image of the attached anodic layer; (D) image of the anodic layer with metal straw sealed by silicon rubber; and (E) image of the fabricated mini-MFC. Two metal plates with screws were used to tightly clamp all layers together.

Compared to the previous mini-MFCs reported in the literature, the mini-MFC fabricated in this work has the highest maximum power density of the reported micro-liter scale MFCs and maximum current density of 29mW/m2 and 2148mA/m2, respectively. The results have been published on Biosensors and Bioelectronics (2011, 26: 2841).