E-skin: a new step into the future

According to recent studies, electronic skin (or e-skin), could play an important role in the realization of the latest generation of prosthesis, in individual medicine, robotics and artificial intelligence (AI).
Electronic skin is basically a tissue that reproduces human skin in terms of strength, elasticity and sensitivity. It is used to collect biological data in real time.
As the author of the Yichen Cai project at King Abdullah University of Science and Technology in Saudi Arabia stated, "the ideal electronic skin is able to imitate the natural functions of human skin, such as touch and temperature detection, accurately and in real time".
However, achieving an appropriately versatile electronics that can perform such complex tasks while withstanding the bumps and scratches of everyday life is an extremely difficult task. In addition, every material that is used must be designed down to the last detail.
Most e-skins are made by layering an active nano-material (the sensor) on an elastic surface that sticks to human skin. The problem is, however, that the connection between these layers is often too weak, and reduces the resistance and sensitivity of the material. On the other hand, if the resistance is too much, the flexibility is limited, making it more likely that the electronic circuit breakage and consequent interruption.
"The world of e-skin continues to move at an incredible pace. The birth of 2D sensors has accelerated work to incorporate these atomically thin and mechanically strong materials into functional and durable artificial leathers," said Cai.
Recently, however, a durable artificial leather type has been created using a hydrogel reinforced with silicon nano-particles. This is used as a strong and elastic substrate, while a second part made of 2D MXene titanium carbide is used as a detection layer, and is bonded together with high-conduction nanowires.
"Hydrogels are more than 70% water-based, which makes them very compatible with human skin tissues," the researchers said.
In fact, by pre-stretching the hydrogel in all directions, applying a layer of nano-strands, and carefully monitoring its release, the team created conductive paths to the sensor layer that remained intact even when the material was stretched to 28 times its original size.
Their e-skin prototype was able to detect objects at a distance of 20 centimeters, respond to stimuli in less than a tenth of a second and, when used as a pressure sensor, distinguished the handwriting written on it. In addition, it continued to function properly even after 5,000 deformations, recovering in about a quarter of a second each time.
"Maintaining strength even after uninterrupted use, for an e-skin, is an extraordinary achievement," the team reported.
Previously, another study published in the journal Advanced Intelligent Systems, reported that researchers at RMIT University in Australia have developed an electronic artificial skin that reacts to pain just like real skin.
This paves the way for better prosthetics, smarter robotics and non-invasive alternatives to skin grafts.