A hypoallergenic electronic sensor can be worn on the skin continuously for a week without discomfort, and is so light and thin that users forget they even have it on, says a group of researchers at the University of Tokyo and their collaborators. The elastic electrode constructed of breathable nanoscale meshes holds promise for the development of noninvasive e-skin devices that can monitor a person’s health continuously over a long period (Nature Nanotechnology, “Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes”).
Wearable electronics that monitor heart rate and other vital health signals have made headway in recent years, with next-generation gadgets employing lightweight, highly elastic materials attached directly onto the skin for more sensitive, precise measurements.
However, although the ultrathin films and rubber sheets used in these devices adhere and conform well to the skin, their lack of breathability is deemed unsafe for long-term use: dermatological tests show the fine, stretchable materials prevent sweating and block airflow around the skin, causing irritation and inflammation, which ultimately could lead to lasting physiological and psychological effects.
“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 at the University of Tokyo’s Graduate School of Engineering whose research group had previously developed an on-skin patch that measured oxygen in blood.
In the current research, the group developed an electrode constructed from nanoscale meshes containing a water-soluble polymer, polyvinyl alcohol (PVA), and a gold layer—materials considered safe and biologically compatible with the body.