A team of Japanese scientists has developed a way of creating breathable on-skin electronics that can stretch while continuing to function and that don’t cause any inflammation on the skin. These tattoo-like electronics have now been worn by volunteers for up to a week, with them reporting that they don’t even feel the presence of the electronics on their skin.
Because previously flexible on-skin electronic devices relied on a substrate surface to lay on top, it blocked the skin from undergoing its normal sweating, cooling, and other processes. The Japanese team managed to laminate electronic sensors and connecting wires directly onto the skin. The magic was the ink that was used, which is a material made of nano-scale gold rods infused into a flexible water-soluble polymer.
The material is simply squeezed and pressed onto the skin. Once a bit of water is applied, the polymer washes away and the gold nanorods remain trapped by the tiny folds within the skin. Gold is known to be a safe metal to contact with the body, so hopefully the nanorods will be too!
Because the nanorods create a hay-like network that stays connected together, it remains intact even after quite a bit of stress. In their study, the researchers bent and stretched their gold mesh-based wires over 10,000 times and they remained functioning throughout.
The researchers also showed that they were able to detect skin temperature and if something is touching it, including how hard.
The bending of the skin can probably also be detected by changes in an electrical current passed through the ink, and things like sweat and other biomarkers probably will also affect the electric signal. That would mean that such technology may soon be used for long-term monitoring of a variety of vital signs and performance parameters.
Study in Nature Nanotechnology: Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes…
Via: University of Tokyo…