Fabrication of Conductive Microparticles as Anodal Electrode in Microfluidic Microbial Fuel Cell

Abstract

Microbial fuel cell (MFC) is developed as a renewable energy source, which can simultaneously carries out wastewater treatment. The ability of microorganism in generating extractable electricity highly affects the performance of a MFC; therefore, it is critical to construct a high throughput analysis platform for microorganism screening. Microfluidic MFCs are recently developed for the rapid analysis; however, several challenges remained to be overcome to construct straightforward techniques. This study presents an innovative anode composed of conductive microparticles for encapsulating electricity-generating microbes in microfluidic MFCs. The conductive polymer microparticles (Diallyldimethylammonium chloride, DADMAC) encapsulating microorganisms were generated by a T-junction microchannel. The surface area per volume of the pDADMAC micro-particle was 2.17x106 cm-1 and it can provide extensive surface area for electron transfer. We first examined the electricity generated from these particles using a batch-type operation. Microparticles containing microbes generated open circuit voltage (OCV) of 8mV in the first hour and the OCV gradually decreased to 0mV in 6hours, indicating the depletion of substrate. Particles without microbes had relatively stable OCV around 1mV throughout the operation except for the first 10min. The conductive microparticles were also applied in an air-cathode batch-type MFC and they increased the OCV from ∼0V to ∼20mV compared with freely suspended microorganisms. These results show the great potential of utilizing the conductive microparticles as anodal electrode in microfluidic microbial fuel cells.