The Rogers Research Group at the University of Illinois at Urbana-Champaign has given us stick-on electronic tattoos and stretchable batteries, but now they’ve outdone themselves by creating the first electronic sensor to be printed directly onto human skin.
The printable sensors are an extension of the groups electronic tattoos and can measure skin hydration, temperature and electric signals from muscle and brain and activity.
Unlike the stick-on electronic tattoos that use an elastic polymer backing and can easily wash off in the shower or swimming pool, the new e-tats do away with the polymer backing and are printed directly on the skin. Doing so made the sensors 1/30th as thick as previous devices and better at conforming to the natural ridges of skin.
“What we’ve found is that you don’t even need the elastomer backing,” John Rogers told Technology Review. “You can use a rubber stamp to just deliver the ultrathin mesh electronics directly to the surface of the skin.”
Once the sensors were printed on the skin, researchers used a commercially available spray-on bandage to protect the electronics. However, due to the skin’s natural exfoliation process, the sensors flaked off after two weeks. Researchers said this is a fundamental flaw of epidermal electronics. To achieve a longer lifespan, sensors would need to be embedded under the skin like read tattoos. Stay tuned. That can’t be far off.
Credit: University of Illinois