An ultra-thin material embedded with electronics that can attach to the skin and monitor blood oxygen levels has been produced by researchers in Japan. Scientists at the University of Tokyo described their prototype ‘e-skin’ as a thin, flexible, organic material that is stable in air. The e-skin has a protective film, comprising five alternating layers of an inorganic and organic material, which protects the onboard electronics from water vapor and air. Polymer light-emitting-diodes (PLED) and organic photo-detectors on the e-skin are used to transmit and detect the light that reflects after passing into a finger. This is used to gauge the blood oxygen and pulse rate which is then displayed on a PLED display.
Wearable technology that monitors body functions is a growing area of biomedical research, but there are many challenges to overcome. Current materials are not thin enough or sufficiently flexible to attach d remain on the body comfortably and unobtrusively for long. Though organic materials presently available reach suitable micrometer-scale thinness and flexibility, but they degrade quickly in air.
The new e-skin developed in Japan appears to overcome many of the problems of previous designs. It enables the creation of ultra-thin and ultra-flexible electronic devices that remain stable in air for several days.
The PLEDs that the team created were only 3 micrometers thick and their efficiency was six times greater than that of previously reported ultra-thin PLEDs. This means they require far less power and produce a lot less heat - making them particularly suitable for attaching directly onto the body.
The researchers hope their e-skin will lead to the creation of devices that measure and display not only blood oxygen and pulse rate but other vital functions.
E-skin technology could also have applications outside medicine, such as athletics, personal fitness and communications and could transform personal communications to the same extent as mobile phones have.