'Hydroprinted' Electronic Skin for Prosthetics and Wearable Health Monitors

Researchers from the University of Coimbra in Portugal and Carnegie Mellon University, reporting in the American Chemical Society journal Applied Materials & Interfaces  , have developed ultrathin, stretchable electronics that can be easily transferred to 3D objects. These circuits could be used in electronic skin to help machines and humans interact. The circuit is fabricated by printing the pattern over a temporary tattoo paper using a desktop laser printer, which is then coated with a silver ink and eutectic gallium–indium (EGaIn) liquid metal alloy. The researchers have demonstrated various medical applications including electronic tattoos for human skin and LEDs transferred over the 3D-printed shell of a robotic prosthetic hand.

Transcript

00:00:00 nerve cells in our skin allow us to experience the many sensations of touch the silky softness of a cat's fur the pre cleanness of cactus needles the heat of a stove scientists are trying to develop electronic skins to bring the sense of touch to robots and prosthetic devices now researchers report a new method in ACS applied materials and interfaces that creates an ultra-thin

00:00:21 stretchable electronic skin which could be used for prosthetics robotics and even wearable health monitors one of the challenges in making electronic skins is transferring electrical circuits onto complex 3d surfaces and these electronics must be bendable and stretchable enough to allow movement current methods for producing these electronics are slow expensive and

00:00:41 requires sophisticated equipment and techniques Mamu tavakoli carmella Majidi and colleagues wanted to develop a fast simple and inexpensive method to produce thin film circuits and integrated micro electronics in the new approach the researchers patterned a circuit template onto a sheet of transfer tattoo paper with an ordinary desktop laser printer then they coated the template with

00:01:03 silver paste which stuck only to the printed toner ink they wiped away the excess silver on top of the silver paste the team deposited a gallium indium liquid metal alloy that increased the flexibility and electrical conductivity of the circuit finally they added external electronics such as microchips with the silver epoxy or a conductive glue made of vertically

00:01:25 aligned magnetic particles embedded in a polyvinyl alcohol gel the researchers used water to help transfer the electronic tattoo to 3d objects they immersed an object in a tub of water and then placed a circuit on the surface of the water the paper backing of the tattoo is separated from the carrier film which floated on the surface of the water when the researchers lifted the

00:01:47 object such as this part of a prosthetic hand out of the water the circuit adhered to the contours of the object the team demonstrated several applications of their new method in one they transferred a circuit to a volunteers arm that allow the person to control a robot prosthetic arm the researchers used an electronic tattoo to monitor human skeletal muscle activity

00:02:08 and placed proximity sensors into a 3d model of a hand the circus worked even after being immersed in water as shown for this circuit with LEDs you