This artificial skin sensor dials hope for wearables

Artificial skin sensors could be the future of wearable and stretchable electronics and keeping that in mind, researchers at University of Toronto Engineering have developed a super-stretchy, transparent and self-powering sensor that records the complex sensations of human skin. Dubbed artificial ionic skin — or AISkin for short — the innovative properties of the sensor could lead to future advancements in wearable electronics, personal health care and robotics.

“Since it’s hydrogel, it’s inexpensive and biocompatible — you can put it on the skin without any toxic effects. It’s also very adhesive, and it doesn’t fall off, so there are so many avenues for this material,” said Professor Xinyu Liu, whose lab is focused on the emerging areas of ionic skin and soft robotics.

AISkin is also uniquely tough and stretchable.

“Our human skin can stretch about 50 per cent, but our AISkin can stretch up to 400 per cent of its length without breaking,” said Binbin Ying, a visiting PhD candidate from McGill University who’s leading the project in Liu’s lab.

The adhesive ‘AISkin’ is made of two oppositely charged sheets of stretchable substances known as hydrogels. By overlaying negative and positive ions, the researchers create what they call a “sensing junction” on the gel’s surface, said the study published in the journal Materials Horizons.

When the AISkin is subjected to strain, humidity or changes in temperature, it generates controlled ion movements across the sensing junction, which can be measured as electrical signals such as voltage or current. The new AISkin could open doors to skin-like Fitbits that measure multiple body parameters, or an adhesive touchpad you can stick onto the surface of your hand.

“It could work for athletes looking to measure the rigour of their training, or it could be a wearable touchpad to play games,” said Liu.

Over the next year, Liu’s lab will be focused on further enhancing their AISkin, aiming to shrink the size of AISkin sensors through microfabrication. “If we further advance this research, this could be something we put on like a ‘smart bandage,’” said Liu.