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The National Science Foundation has awarded a $452,000 grant to faculty at �������� for research to generate power from human sweat.

Seokheun “Sean” Choi, associate professor of electrical and computer engineering, and Ahyeon Koh, assistant professor of biomedical engineering, will attempt to generate an innovative, practical and longstanding power source from human sweat, which is one of the few available energy resources on the skin, by using the metabolisms of sweat-eating bacteria. Their project is titled “Power-on-Skin: Energy Generation from Sweat-Eating Bacteria for Self-Powered Electronic Skins.” Electronics skin, or e-skin, refers to flexible, stretchable and self-healing electronics that are able to mimic the functionalities of human skin.

Choi said that sweat-based power sources have a lot of potential. Devices that scavenge energy from sweat could be a superior substitute for conventional batteries, energy storage devices and other energy harvesting devices for future e-skin applications.

“Among many energy-harvesting devices for e-skins, biochemical energy harvesting from human sweat is arguably the most underdeveloped because of immature technologies,” said Choi. “Nonetheless, excitement is building for scavenging power from sweat, as it is the most suitable energy source for skin-contacting devices. Sweat is readily and constantly available in sufficient quantities, can be acquired non-invasively, and contains a rich variety of chemical and biological entities that can produce electricity.”

E-skins have recently emerged as a novel platform for electronics, taking on more important roles in health diagnostics, therapeutics and monitoring. Stand-alone and self-sustained e-skins are essential to providing reliable, effective and sometimes life-saving functions, and Choi said these devices are the future of technology.

“Electronic skins or ‘e-skins’ have now reached the ‘tipping point’,” said Choi. “With the development of stretchable, biocompatible and self-healing electronic materials, significant research efforts are dedicated to the seamless and intimate integration of electronics with human skin, which will produce breakthroughs in human-machine interfaces, health monitoring, transdermal drug delivery and soft robotics. As the emerging technologies of artificial intelligence and the internet of things are advancing at a rapid pace, e-skins will definitely be one of the ultimate forms of next-generation electronics.”

While e-skins provide many benefits, they require a stable power supply. Therefore, a realistic and accessible power source is urgently needed for a next-generation of smart, stand-alone, always-on e-skin systems. However, this is a challenge because human skin intimately integrated with e-skins is an extremely harsh environment for power generation, as skin is cool, dry, acidic and lacks potential energy sources. Thus, researchers believe that using the metabolisms of sweat-eating bacteria, including human skin microorganisms or ammonia-oxidizing microorganisms, will successfully create a power source for new e-skins.

“The proposed sweat-powered batteries will be based on microbial fuel cells (MFCs), which will exploit sweat-eating bacteria to transform the chemical energy of sweat into electrical power through bacterial metabolism,” said Choi.

While sweat-generated batteries are intended to power e-skins, Choi said this project has the potential to impact more than just the e-skin market.

“Scientific knowledge gained from this project will have far-reaching implications and support long-term goals of a truly stand-alone and self-powered e-skin that operates independently and self-sustainably,” said Choi. “The project outcomes will address grand challenges in sensing and power sectors critical to U.S. security and competitiveness, through enabling skin-mountable electronics that will augment human capabilities, and well-being by providing a tool that can improve many healthcare devices. Therefore, the proposed research has potentially far-reaching social and economic effects linked to health monitors, human-machine interfaces, soft robotics, medical therapies and disease diagnostics.