Advances in Miniaturized Microbial Fuel Cells: Components, Performance, and Biosensing Applications

ABSTRACT

Microbial fuel cells (MFCs) are bioelectrochemical systems that convert chemical energy from organic substrates into electricity through microbial metabolism. Recently, miniaturized MFCs have attracted increasing interest since reducing device size can potentially increase surface‐area‐to‐volume ratio and decrease diffusion distance while supporting integration with microfluidics and low‐power electronics. Moving these devices from stand‐alone power generation devices toward field deployable self‐sustained bioelectronic platforms would require system level optimization involving three critical aspects: (i) novel anode materials and architectures to enhance performance through promoting rapid biofilm formation, (ii) cathode materials and oxygen reduction reaction (ORR) catalysts, which are responsible for stabilizing power generation and microbial activity, and (iii) miniaturized intricate device designs that offer innovative stacking schemes, advanced fabrication techniques, and biosensing operation. We summarize state‐of‐the‐art strategies that can be implemented for anode optimization (such as nanostructuring, three‐dimensional [3D] scaffolds, and surface functionalization), discuss ORR, and compare the performance of micro‐MFC platforms reported in recent literature in terms of power generation and usability in biosensing applications. Finally, we highlight engineering bottlenecks, including durability, membrane or separator limitations, and cost‐effective fabrication, and propose practical design directions to move miniaturized MFCs from proof‐of‐concept demonstrations to robust, application‐specific energy sources and biosensing devices.