Researchers from the University of California, San Diego have developed a skin-based biofuel cell powered by human sweat. The research was published June 15 in the journal Energy & Environmental Science.

Image credit: Kullez / CC BY 2.0Image credit: Kullez / CC BY 2.0The device, which the researchers call an electronic skin-based biofuel cell (E-BFC), exhibits an open circuit voltage of 0.5 V. It also exhibits a power density of 1.2 mW/cm-2 at 0.2 V, the highest recorded by a biofuel cell to date. When applied directly to the skin, the E-BFC can generate around 1 mW of power, enough to power an LED of low-power Bluetooth radio.

The article summary states: “Successful generation of high power density under practical conditions and powering of conventional energy-intense electronic devices represents a major step forward in the field of soft, stretchable, wearable energy harvesting devices.”

The researchers use the lactate found in sweat to power the E-BFC. The amount of lactate or lactic acid in sweat is related to how efficiently a person’s muscles are working, so a future device could also help give readings on an athlete’s performance during exercise. Glucose levels in sweat are also related to its concentration in the blood. A device similar to the E-BFC could therefore be developed to potentially monitor glucose levels in diabetics, eliminating the need for needles or blood samples.