Electronic skin stretched to new limits

"Our material outperforms all previously reported hydrogels and introduces new functionalities," claims Professor Husam Alshareef of KAUST.

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%, the material can quickly return to its original form and will adhere to many surfaces, including skin. When cut into pieces, it can also quickly mend itself upon reattachment.

"The material's differing sensitivity to stretching and compression is a breakthrough discovery that adds a new dimension to the sensing capability of hydrogels," says first author, Yizhou Zhang of KAUST.

The team believes there is “real potential” for the material in various biosensing and biomedical applications.

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.

Strips of the material attached to the throat have impressive abilities to convert speech into electronic signals. This might allow people with speech difficulties to be clearly heard.

Other medical applications could 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.

An ideal potential would be to combine both medical sensing and therapy. Other possibilities lie in robotics, the researchers add, where the material could, for example, serve in touch-sensitive finger-like extensions for machinery.

There are also anti-counterfeiting possibilities, with slabs of the material and integrated electronics proving highly sensitive at detecting signatures as they are written.

The KAUST team have a long list of possible applications that they are looking to explored and develop further.