Key points from article :
Small biofuel cells can harvest enough energy from sweat on fingertips to power wearable medical sensors.
As fingertips are one of the sweatiest parts of the body, the sensors could be powered all day.
Biofuel cells that fit into thin pads are stuck to the fingertips.
They soak up sweat into a thin layer of foam, where an enzyme oxidises lactate in sweat to create an electrical charge.
Each finger pad can generate 20-40 microwatts of power and harvest 300 millijoules of energy per sqcm during 10 hours of sleep.
This is more than enough for lightweight sensors that detect a range of metrics such as heart rate, vitamin deficiencies and glucose levels.
Produce continuous charge even if the wearer isn’t exercising.
Currently, the enzyme begins to break down and become ineffective after two weeks.
Further research is needed to create a stable enzyme that can be used in permanent sensors.
Research by University of California, San Diego published in the journal Joule.