A microsized microbial fuel cell based biosensor for fast and sensitive detection of toxic substances in water

We report a microliter-sized (140 μL) microbial fuel cell (MFC)-based biosensor integrated with a three-electrode configuration and an air-bubble trap, in which microorganisms act as the sensor for toxic substances in water. The small-scale MFC biosensor produced favorable conditions for (i) reducing measurement time by increasing the probability of cell attachment and biofilm formation in the micro-sized chamber and (ii) enhancing sensitivity and reliability by providing a stable anodic potential and preventing air bubbles on the sensing surface. Using formaldehyde as a toxic component, the rapid current responses were obtained over a concentration range from 0.001% to 0.1% in a single chambered MFC biosensor with 0.2 V (versus Ag/AgCl reference electrode) applied on the anode.