Saliva fuel cell mooted for powering medical testers in the field

“On-demand micro-power generation is required especially for point-of-care diagnostic applications in developing countries,” said researcher Seokheun Choi. “Typically, those applications require only several tens of microwatt-level power for several minutes, but commercial batteries or other energy harvesting technologies are too expensive and over-qualified.”

Power density is a few μW/cm2. 16 cells connected in series, from a single sheet of paper, generated enough to power an LED. “Further power improvement is required for other electronic applications demanding hundreds of milliwatts of energy,” said Choi.

According to the abstract of ‘A papertronic, on-demand and disposable biobattery: Saliva-activated electricity generation from lyophilized exoelectrogens preinoculated on paper‘, published in Advanced Materials Technologies, the microbial fuel cells have freeze-dried bacteria, which have a long shelf-life (tested up to four months), and generate power within minutes of adding saliva.