A paper-based microbial sensor array for rapid screening of electricity-producing bacteria

Abstract

We demonstrate the use of paper-based test platforms for rapid characterization of electricity-generating bacteria. The presented device contains vertically stacked anode/cathode paper chambers (or reservoirs) separated by a proton exchange membrane (PEM), and gold anode/cathode interface pads with through-holes in the center to introduce anolyte/catholyte. The paper-based sensor exploits the paper’s ability to quickly wick fluid and promote bacterial attachment to the gold anode pads, resulting in instant current generation upon loading of the bacterial inoculum and catholyte. Within just 50 minutes, we successfully determined the electricity generation capacity of two known bacterial electrogens and another metabolically more voracious organism with four isogenic mutants. This paper-based microbial screening tool does not require external pumps/tubings and represents the most rapid test platform (<50 min) compared with the time needed by using traditional screening tools (up to 103 days) and even recently proposed MEMS arrays (< 2 days).