Ultra-thin electronics, which can be placed on the skin as easily as a temporary tattoo, could pave the way for patient monitoring systems that would avoid the need for bulky equipment.
In one study, the adhesive patch was applied to a person's chest to pick up electrical signals produced by the heart. The measurements agreed "remarkably well" with those produced by a hospital electrocardiogram, according to the researchers.
John Rogers, PhD, and colleagues at the University of Illinois and other institutions in the U.S., Singapore, and China, have developed a system "of epidermal electronics" that almost exactly match the properties of the skin.
The patch contains electronic monitors that are integrated onto a water-soluble polyester backing (elastomer). It is attached to the body by brushing it with water. Weak forces of attraction between the skin and the backing cause the patch to stick to the skin like super-adhesive cling film. The patch is extremely thin -- less than the diameter of a human hair.
"The skin represents one of the most natural places to integrate electronics. As the largest organ in the body, and our primary sensory mode of interaction with the world, it plays a special role," Rogers says.
In their study, reported in Science, the researchers note that the patch has been worn effectively for 24 hours without irritating the skin. However, because surface cells in the skin are constantly being shed and renewed, a new one would have to be attached at least every two weeks. The patch also still needs to be tested with range of skin conditions, from dry to sweaty.
"Ultimately, we think that [our] efforts can blur the distinction between electronics and biology," Rogers says.