Finger sweat can power wearable medical sensors 24 hours per day

Finger sweat can power wearable medical sensors 24 hours per day

Small biofuel cells can harvest enough energy from the sweat on a person’s fingertips to power wearable medical sensors that track health insurance and nutrition – and because our fingertips are among the sweatiest areas of the body, the sensors could be powered all day long.

Lu Yin at the University of California, San Diego, and his colleagues created a device that reduces a dissolved compound in sweat called lactate. It comprises biofuel cells that fit into thin pads that are stuck to the fingertips. They absorb sweat right into a thin layer of foam, where an enzyme oxidises lactate in the sweat to create an electrical charge.

Each finger pad can generate 20 to 40 microwatts of power and harvest 300 millijoules of energy per square centimetre during 10 hours of sleep. This isn’t enough to perform power-hungry devices like smartwatches or cell phones, but more than enough for lightweight sensors that discover a range of metrics such as for example heartrate, vitamin deficiencies and sugar levels.

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Researchers have created devices that are powered by sweat before, nevertheless they needed large volumes of the liquid, such as when a subject was jogging. The fingertips have the best concentration of sweat glands on your body and produce continuous charge whether or not the wearer isn’t exercising.

“Despite having when amount of sweat compared to the sweat you have from a really powerful workout, this power continues to be very sizeable,” says Yin. “Regardless of how clean your hand is, it’s very simple to leave your fingerprint everywhere. That’s basically the residue of your sweat, with a whole lot of metabolites. What we did is to take advantage of this.”

Currently, the enzyme that’s key to the reaction begins to break down and become ineffective after two weeks. Yin says that further research is required to create a well balanced enzyme that can be utilized in everlasting sensors.

Journal reference: Joule , DOI: https://www.cell.com/joule/fulltext/S2542-4351(21)00292-0

Read more: Radio powered by your own sweat hints at future of wearables

More on these topics:

  • sensors
  • wearables
  • biofuel

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