Breathable electronic skin patch developed for continuous long-term use

Scientists have developed an electronic sensor that is hypoallergenic, breathable and can be worn constantly for a week, enabling continuous, unobtrusive health monitoring.

The patch, developed by scientists at the University of Tokyo, is, according to its creators, so thin and light that the majority of users will forget they are even wearing it – a far cry from many of the weighty or uncomfortable health monitoring solutions currently available.

Designed to withstand repeated and continuous bending and stretching, the patch can be worn during a host of day-to-day activities, including sports. As a result its creators believe it could be used not only in healthcare settings, but also to monitor professional athletes.

“It will become possible to monitor patients’ vital signs without causing any stress or discomfort,” said Professor Takao Someya, from the University of Tokyo’s Graduate School of Engineering.

The patch, which is detailed in research published today in the journal Nature Nanotechnology, is a step forward due to its breathable properties, allowing it to be worn for far longer than other ultrathin patches, which are made of rubber and other similarly non-breathable materials.

It consists of an electrode made up of several nanoscale meshes, which contain a water-soluble polymer, polyvinyl alcohol (PVA) and a thin layer of gold.

The patch is applied to the skin by spraying it with a thin layer of water, which dissolves the PVA and leaves the patch able to stick to the skin. It is even designed to adhere to the minute bumps in the skin, including sweat pores and the ridges that form human fingerprints, allowing a snug fit and good long-term attachment.

Currently it has been tested on 20 study participants, who wore the patch for a week. Not one experienced any inflammation, suggesting the patch should be suitable for wide-scale medical use.

It was also successfully bent and stretched over 10,000 times without damage, and was successfully used as an electrode to record electromyogram readings, which measure the electrical activity muscles, at similar levels to standard gel electrodes.

A diagram showing how the patch adheres to the skin. Images courtesy of Someya Laboratory, 2017.

The scientists have previously developed a patch that measures blood oxygen, and decided to create this variant upon realising the significant medical need for comfortable patches that can be worn constantly for significant periods.

“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,” said Someya.

While the headline use for the patch will undoubtedly be in medical settings, it is also likely to attract considerable interest in the world of professional sports, where monitoring athletes is becoming increasingly commonplace.

 

At present, most of the wearables used to monitor athletes are housed in plastic units that are temporarily attached to the skin using harnesses or pockets in sports equipment, however such a patch could enable a less obtrusive approach to monitoring.

Wearables breakthrough: Scientists develop missing link for affordable power-generating clothes

Off-the-shelf clothing that can power small electronics on the move is closer than ever before thanks to a breakthrough by materials scientists.

Devised by scientists at the University of Massachusetts, the development takes the form of a new method of applying metal-free electrodes to both fabric and fully formed clothing, which are both breathable and bend and move with the garment.

This has been achieved through the use of a conducting polymer coating, which is applied to regular fabric as a vapour to produce a nanometers-thick layer that does not change the way the fabric feels, or how it needs to be cared for.  Paired with a different material, the technology uses movement-created friction to generate power.

The result is clothes that are both comfortable to wear and which can power small electronics that are either attached to or integrated with the garment. It represents a major advance on the plastic mounts or heavy cladded fibres that have previously been used to add electronics to fabrics, putting an end to uncomfortable plastic lumps or heavy additions that warp the shape of clothing.

The conductive polymer is applied as a vapour, meaning it has a maximum thickness of just 500 nanometers.

It is thought that the technology could be used for health monitoring, which is increasingly being used by both the military and the healthcare industry.

“We aim to build up the materials science so you can give us any garment you want, any fabric, any weave type, and turn it into a conductor,” explained Trisha Andrew, from the University of Massachusetts Amherst.

“Such conducting textiles can then be built up into sophisticated electronics. One such application is to harvest body motion energy and convert it into electricity in such a way that every time you move, it generates power.

“By sandwiching layers of differently materials between two conducting electrodes, a few microwatts of power can be generated when we move.”

The technology could be used in healthcare to create garments that continuously monitor patient health without creating discomfort.

The technology, which is detailed in a paper published the journal Advanced Functional Materials, is also designed to be very robust, enabling it to be stretched, pulled and washed like normal garments.

“You’d be amazed how much stress your clothes go through until you try to make a coating that will survive a shirt being pulled over the head. The stress can be huge, up to a thousand newtons of force. For comparison, one footstep is equal to about 10 newtons, so it’s yanking hard,” said Andrew.

“If your coating is not stable, a single pull like that will flake it all off. That’s why we had to show that we could bend it, rub it and torture it. That is a very powerful requirement to move forward.”

Designed to work with conventional fabrics, the technology will likely be embraced by the textiles and fashion industry, particularly among sportswear brands that have already heavily explored adding technology to their clothing.

“There is strong motivation to use something that is already familiar, such as cotton/silk thread, fabrics and clothes, and imperceptibly adapting it to a new technological application,” said Andrew.

“This is a huge leap for consumer products, if you don’t have to convince people to wear something different than what they are already wearing.”