Electronic skin stretched to new limits

A research team in Saudi Arabia have found that metal carbide within a hydrogel composite senses, stretches and heals like human skin for use in medicine and robotics.

The material is a composite of the water-containing hydrogel and a metal-carbide compound known as MXene. As well as being able to stretch by more than 3400 percent, the material can quickly return to its original form and will adhere to many surfaces, including skin. When cut into pieces, it can quickly mend itself upon reattachment.

“Our material outperforms all previously reported hydrogels and introduces new functionalities,” says Husam Alshareef, professor of materials science and engineering at the King Abdullah University of Science and Technology.

The material’s differing sensitivity to stretching and compression is a breakthrough discovery that adds a new dimension to the sensing capability of hydrogels. This new dimension may be crucial in applications that sense changes in the skin and convert them into electronic signals. A thin slab of the material attached to a user’s forehead, for example, can distinguish between different facial expressions, such as a smile or a frown. This ability could allow patients with extreme paralysis to control electronic equipment and communicate.

“There is real potential for our material in various biosensing and biomedical applications,” says co-author Kanghyuck Lee.

More straightforward and extremely useful medical possibilities include flexible wound coverings that can release drugs to promote healing. These could be applied internally, on diseased organs, in addition to adhering externally to skin. The team also envisions developing a smart material that could monitor the volume and shape of an organ and vary drug release according to signals produced.