AISkin gets a grip on human skin sensations

The complex sensations of human skin can now be recorded by AISkin, a transparent and self-powering sensor developed by engineering researchers in Canada.

AISkin demonstrated by PhD candidate Binbin Ying (Image: Daria Perevezentsev)

The team from the University of Toronto believe the properties of AISkin (artificial ionic skin) could lead to advances 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 Prof Xinyu Liu, whose lab focuses on the emerging areas of ionic skin and soft robotics.

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According to the University of Toronto, AISkin is made of two oppositely charged sheets of hydrogels. By overlaying negative and positive ions, the researchers create a so-called “sensing junction” on the gel’s surface.

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.

“If you look at human skin, how we sense heat or pressure, our neural cells transmit information through ions — it’s really not so different from our artificial skin,” Liu said in a statement.

AISkin is also claimed to be 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 researchers have published their findings in Materials Horizons.

The new AISkin could lead to skin-like Fitbits that measure multiple body parameters, or an adhesive touchpad that could be stuck to the surface of a human 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.

It could also measure the progress of muscle rehabilitation. “If you were to put this material on a glove of a patient rehabilitating their hand for example, the health care workers would be able to monitor their finger-bending movements,” said Liu.

The researchers further envision AISkin being integrated onto soft robots to measure data, whether it’s the temperature of food or the pressure necessary to handle brittle objects.

The University added that 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. They’ll also add bio-sensing capabilities to the material, allowing it to measure biomolecules in body fluids.

“If we further advance this research, this could be something we put on like a ‘smart bandage,'” said Liu. “Wound healing requires breathability, moisture balance – ionic skin feels like the natural next step.”