Researchers at the University of Tokyo have developed a mesh-based substance known as nanomesh that could be used to make wearable health monitors.
The research could lead to the development of non-invasive ‘e-skin’ devices that can monitor a person’s health continuously over a long period.
The breathable electronic skin can be safely worn for a week without causing any skin complaints. The researchers claim that the device is so light and thin that users forget they even have it on.
Wearable devices to monitor health conditions have come some way in recent years, with many devices coming onto the market that use highly elastic materials attached directly onto the skin for more sensitive, precise measurements. But many of these come with problems in that while ultrathin films and rubber sheets used in these devices stick well to the skin, they aren’t that breathable, posing risks for long-term use, such as preventing sweating and blocking airflow around the skin, causing irritation and inflammation.
Nanomesh long-term use
“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 Professor Takao Someya at the University of Tokyo’s Graduate School of Engineering, whose research group previously developed an on-skin patch that measured blood oxygen.
The team has developed an electrode made from nanoscale meshes containing a water-soluble polymer, polyvinyl alcohol (PVA), and a gold layer – all materials that are considered safe. The device can be applied by spraying a tiny amount of water, which dissolves the PVA nanofibers and allows it to stick easily to the skin. It can even conform to the shape of sweat pores and ridges of the skin.
The team then carried out skin patch tests on 20 people and found that after a week, there were no signs of inflammation or irritation. It also tested the device’s mechanical durability through repeated bending and stretching of a conductor attached on the forefinger, in excess of 10,000 times. The researchers found that the mesh was as reliable as an electrode for electromyogram recordings, where its readings of the electrical activity of muscles were comparable to those obtained through conventional gel electrodes.
“It will become possible to monitor patients’ vital signs without causing any stress or discomfort,” said Someya.
As well as medical applications, the new device could allow continuous, precise monitoring of athletes’ physiological signals and bodily motion without hindering training.