New Sweat-based Device can Produce Power from Your Sweaty Fingertips

Sweat-based power generators always have their unique place in the market. Researchers now developed unique biofuel cells that can power wearable electronics by making use of our sweaty fingertips.

Researchers at the University of California San Diego developed a novel device that can generate power through our fingertips. The device makes use of our sweat as fingertips have the highest concentration of sweat glands in the body.

The team published the story of their complete research in the journal Joule .

Wearable Sensors to Decode Sweat Composition
New non-invasive wearable sensors can detect the composition of sweat such as sweat rate, electrolytes, and metabolites.

‘Lactate is a metabolic by-product excreted in sweat. The new bio enzyme-based power generators produce energy using this molecule by a series of chemical reactions.’

There were many similar devices in the past where most of them required intense physical activities by the user. This device cancels out such needs by making use of our sweaty fingers to power some small wearable electronics during sleep.

"Normally, you want maximum return on investment in energy. You don't want to expend a lot of energy through exercise to get only a little energy back. But here, we wanted to create a device adapted to daily activity that requires almost no energy investment. You can completely forget about the device and go to sleep or do desk work like typing, yet still continue to generate energy. You can call it 'power from doing nothing,” said Joseph Wang, senior author of the study.

Biofuel cell that uses lactate

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The novel device was designed based on the concept of a biofuel cell (BFC). A foam made of carbon nanotube material and some hydrogel components make this device unique. The product contains a bio enzyme that acts upon the lactate molecules present in our sweat. Once the enzyme comes into contact with the sweat, electrons are removed from the lactate molecules and a series of biochemical reactions occur, creating a current of electricity.

This setup does not cause any inconvenience to the users. "The size of the device is about one centimeter squared. Its material is flexible as well, so you don't need to worry about it being too rigid or feeling weird. You can comfortably wear it for an extended period of time," said Yin, a nanoengineering Ph.D. student working in Wang's lab.

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Improved efficacy with add-ons

The team tested the efficacy of the product after adding piezoelectric generators that convert mechanical energy into electricity. It helped to harvest up to 20% additional energy. The new design was also capable of generating power to run vitamin C- and sodium-sensing systems.

Generate Energy for Small Devices from the Knee by Walking
Energy harvesters that power small electronics with biomechanical energy by bending movements of joints such as the knee, during walking at no cost to the human have been developed.

Apart from this, the team is keen to improve their design further to make it suitable for health and wellness applications such as glucose meters. "We want to make this device more tightly integrated in wearable forms, like gloves. We're also exploring the possibility of enabling wireless connections to mobile devices for extended continuous sensing. There's a lot of exciting potential. We have ten fingers to play with," highlighted Yin.

Source-Medindia