Skin-like Sensors Help Advance AISkin

A group of researchers from the University of Toronto have developed super-stretchy, transparent, and self-powering sensors that will help advance artificial ionic skin. The sensor is able to record the complex sensations of human skin, which was one of the big barriers to developing artificial skin similar to the real thing. 

The new technology is being called AISkin, and the researchers believe that the new technology will be important in wearable electronics, personal health care, and robotics. 

Professor Xinyu Liu’s lab is working on the breakthrough areas of ionic skin and soft 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,” according to Professor Liu.

The AISkin is adhesive, and it consists of two oppositely charged sheets of stretchable substances. Those substances are known as hydrogels. The researchers overlay negative and positive ions in order to create a “sensing junction” on the surface of the gel.

The sensing junction works whenever the AISkin is subjected to strain, humidity, or changes in temperature, which cause controlled ion movements across it. Those can then 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,” says Liu.

The AISkin is both tough and stretchable.

Binbin Ying is a visiting PhD candidate from McGill University, and he is leading the project in Liu’s lab. 

According to Ying, “Our human skin can stretch about 50 percent, but our AISkin can stretch up to 400 percent of its length without breaking.” 

The researchers published their findings in Materials Horizons.

The new AISkin can lead to the development of certain technologies such as skin-like Fitbits that are capable of measuring multiple body parameters. Other technologies include an adhesive touchpad that is able to 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,” according to Liu.

The technology could also measure the progress that is made in 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,” says Liu.

The technology could also play a role within the field of soft robotics, or flexible bots made out of polymers. One of the uses could be with soft robotic grippers that handle delicate objects within factories.

The researchers hope that AISkin will be integrated onto soft robots in order to measure data, such as the temperature of food or the pressure required to handle certain objects.

The lab will now work on advancing AISkin and decreasing the size of the sensors. Bio-sensing capabilities will be added to the material, which will allow it to measure biomolecules in body fluids. 

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