Development of wearable electronics has been accelerating over the past few years. From gold-leaf smart tattoos to thin wearable circuits capable of 5G wireless communications, there have been plenty of innovative ideas, but for a wearable electronic sensor to be truly practical it would need to be comfortable when worn for extended periods of time. A team at the University of Tokyo has now developed a breathable nanoscale mesh that can be safely worn for a week without causing any skin irritation.

"We learned that devices that can be worn for a week or longer for continuous monitoring were needed for practical use in medical and sports applications," says Professor Takao Someya from the University of Tokyo's Graduate School of Engineering.

The problem researchers have faced is that the plastic films and sheets these thin wearable electronics are normally embedded in lack breathability. As a result the materials are often stifle sweating and result in skin irritation or inflammation when worn for extended periods of time.

The University of Tokyo team has developed a nanoscale mesh from a water-soluble polymer, polyvinyl alcohol (PVA), and a gold layer. When the device is applied to the skin and sprayed with a small amount of water, the PVA nano fibers dissolve, resulting in it seamlessly conforming to the contours of the skin.

After testing the device for one week on 20 subjects no skin inflammation was detected. Specific gas permeability was also tested and the porous mesh structure was found to be significantly more breathable than other materials, such as rubber sheets or ultra thin plastic foil.

It's hoped the device will prove practical for both medical and athletic applications. As well as allowing athletes to track their performance over time, continuous and precise monitoring of physiological signals from elastic wearable electronics would be significantly useful in hospitals and nursing homes.

"It will become possible to monitor patients' vital signs without causing any stress or discomfort," adds Professor Someya.

The team's research was recently published in the journal Nature Nanotechnology.

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