Your smart watch running out of battery while on your wrist may soon be a thing of the past, thanks to new technology that uses sweat to power the device.
Researchers from the University of Massachusetts Amherst have discovered how to engineer a biofilm that harvests the energy in evaporation and converts it to electricity.
"This is a very exciting technology," Xiaomeng Liu, the paper's lead author, said. "It is real green energy, and unlike other so-called 'green-energy' sources, its production is totally green."
Liu, a UMass Amherst's College of Engineering graduate, and his team used an engineered version of a bacteria called Geobacter sulfurreducens to produce the biofilm; a thin sheet of bacterial cells no thicker than a sheet of paper. G. sulfurreducensis, which produces energy, has been used in "microbial batteries" to power electrical devices, but the bacteria are required to be alive - meaning it needs to be cared for and fed.
However, the engineered biofilm is dead and therefore doesn't need a food source. Instead, it makes energy from the skin's moisture.
Senior author Derek Lovley, a Distinguished Professor of Microbiology at UMass Amherst, explained: "It's much more efficient. We've simplified the process of generating electricity by radically cutting back on the amount of processing needed. We sustainably grow the cells in a biofilm, and then use that agglomeration of cells. This cuts the energy inputs, makes everything simpler and widens the potential applications."
The thin biofilm can be worn like an adhesive bandage directly onto the skin, taking away the need for bulky batteries.