Batteries powered by bacteria could prove highly useful in offering spurts of electricity where it isn’t readily available, maybe running low-energy diagnostic devices in the developing world, for example. Seokheun Choi, a Computer Science Assistant at Binghamton University, has been investigating these possibilities over the last five years, developing origami-style and ninja-star-like paper batteries that are powered by dirty water. His latest breakthrough battery design calls only on bodily fluids, and was able to power an LED light using a single drop of spit.
These types of bacteria-based batteries rely on what are known as microbial fuel cells (MFCs). These cells use bacteria to carry out reduction/oxidation reactions, which swap electrons between molecules to produce electricity. We have seen this process fuelled by dirty water, in the examples mentioned above, but also urine and now saliva too.
For his latest paper-based battery, Choi uses MFCs built from inactive, freeze-dried exoelectrogenic cells, which can be kept for long periods and generate power within minutes of adding saliva.
“Freeze-drying technique is to store the bacterial cells in the device for a long-term period,” he explains to New Atlas. “Bacterial electricity has long been studied. During their respiration by consuming organic materials like saliva, bacteria can transfer electrons to the external electrode.”
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