Soon your workouts may do more than power up your health. They could also power up small devices like your smartphone.
A team at the UC San Diego has developed an exciting way to harness energy from sweat using a temporary tattoo, according to the American Chemical Society (ACS).
The process is built on lactate – a byproduct of exercise. The UC San Diego group, led by Professor Joseph Wang, placed a small, flexible lactate sensor on a temporary tattoo – which look more business logo than the brightly colored unicorn or Mutant Ninja Turtles shapes of your childhood.
When they peeled the tattoos onto volunteers’ arms, the sensors stripped electrons from the lactate using a special enzyme, and those electrons generated a weak electrical current.
“So we can make this idea of harvesting energy directly from the body in a non-invasive manner,” said Wang in an ACS YouTube video on the topic. “So this is the first example of the biofuel cell that harvests energy from body fluid like sweat.”
The researchers then built a sweat-powered biobattery to harness small amounts of electricity.
Placing 15 tattoo-bearing volunteers on a stationary bike, the team tracked how much power each person generated over 30 minutes.
They discovered people who exercised fewer than once a week produced more power than those who worked out between one to three times a week. According to the ACS, the researchers explained this is because less-fit people get tired faster and produce more lactate.
The maximum amount of energy created by the top volunteer was 70 microwatts per square centimeter of skin – a far cry from the amount of energy needed to power a phone. The average smartphone requires 35 milliwatts each hour, according to Mashable.
“So besides working to get higher power, we also need to leverage electronics to store the generated current and make it sufficient for these requirements,” team member Wenzhao Jia, Ph.D. told the ACS.
Once they figure out how to store energy more efficiently, maybe then they’ll work on tattoo design – at least a flower or star or something.