Researchers have shown that a battery activated by spit has the potential to power point-of-care diagnostic applications in extreme conditions.
In a paper published in the journal Advanced Materials Technologies, the researchers described how they created a high-performance, paper-based, bacteria-powered battery which generates power within minutes of adding saliva.
They created the battery by building microbial fuel cells with inactive, freeze-dried exoelectrogenic cells.
"On-demand micro-power generation is required, especially for point-of-care diagnostic applications in developing countries," said Seokheun Choi, Assistant Professor, Binghamton University, State University of New York.
"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. Also, they pose environmental pollution issues," Choi added.
The battery generated reliable power with one drop of saliva, supplying on-board power that could be used by the next generation of disposable, paper-based point-of-care diagnostic platforms.
"The proposed battery has competitive advantages over other conventional power solutions because the biological fluid for on-demand battery activation is readily available even in the most resource-constrained settings, and the freeze-drying technology enables long-term storage of cells without degradation or denaturation," wrote the researchers.
Choi now wants to improve the batter's power density so that more applications can be powered.
"Now, our power density is about a few microwatts per centimetre square. Although 16 microbial fuel cells connected in a series on a single sheet of paper generated desired values of electrical current and voltage to power a light-emitting diode (LED), further power improvement is required for other electronic applications demanding hundreds of milliwatts of energy," Choi said.