A Skin-Mountable Bacteria-Powered Battery System for Self-Powered Medical Devices

Biochemical energy harvesting from human sweat is arguably the most underdeveloped because of immature technologies. Nonetheless, excitement is building for scavenging power from sweat, as it is the most suitable energy source for skin-contacting wearable devices. Despite the vast potential and promise of sweat-driven power generation, the technique is limited to unstable and inefficient enzymatic catalysis, which requires fundamental breakthroughs to enable self-sustaining, long-lived power generation. Here, we for the first time demonstrate the ability to generate an innovative, practical, and longstanding power from human sweat by using the metabolisms of human skin-inhabiting bacteria, Staphylococcus epidermidis. Our sweat-powered battery was based on microbial fuel cells (MFCs), exploiting the sweat-eating bacteria as a biocatalyst to transform the chemical energy of sweat into electrical power through bacterial metabolism. A DC/DC booster circuit was connected to the stacked devices to increase the operational voltage (∼500 mV) to a maximum output of >3 V for powering a thermometer.