Chinese scientists create "real-life skin": injuries heal completely within 1 hour

Produced by: Science Popularization China

Author: Pan Baohai and Ying Wu Bin (Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences)

Producer: China Science Expo

We always have the feeling that the more human-like a robot is, the higher its technological content is.

This is not human narcissism. Life is the most complex and sophisticated "machine" in nature. It can simulate creatures in nature and also symbolizes the progress of science and technology.

With the development of robotics technology, humans have an increasing demand for humanoid robots. This is not only because robots can complete tasks that humans cannot, but also because robots can simulate human appearance and movements, making it easier for humans to accept them.

But now, when we think of robots, the first thing that comes to mind is still the cold metal surface. In order to make robots closer to real humans, we need to work hard on the "skin". The key technology is what we will introduce today - "human-like skin", also known as ionic skin.

Unimaginable "real-life" ion skin

The capabilities of ionic skin may be beyond your imagination. It can simulate the structure and properties of human skin. It is not only elastic but also able to withstand force.

Ionic skin is a biomimetic material made of biocompatible polyurethane and ionic liquid. This material can sense external force and pressure and transmit signals to the circuit system, allowing the system to record relevant data or respond.

As the name suggests, ionic skin must be related to ions, right? It is indeed true.

We know that the human body's sensory system relies on Na+, K+ and other plasmas to transmit signals. When external forces cause differences in ion concentrations inside and outside the epidermal cells, people can sense them. Ionic skin also detects external stress by detecting the state of ions, that is, the action of external forces will change the state of ions in the material and cause changes in electrical signals.

The structure of human skin and the design concept of ionic skin (Image source: self-made by the author)

The application scenarios of ionic skin may also exceed your imagination. It has wide application value in both the field of robotics and the field of wearable medicine. In the field of robotics, ionic skin can make robots more intelligent and better interact with humans. In the field of wearable medicine, ionic skin can be used to monitor human health and treat certain diseases.

However, although ionic skin can simulate certain characteristics of human skin, it cannot be directly used to replace human skin at present. This is because the materials and manufacturing processes of ionic skin are not mature enough, and the interaction between electronic signals and the human brain is not in-depth enough, which requires further research and improvement.

New ionic skin that heals itself and is super sensitive

The Ningbo Institute of Materials Technology and Engineering of the Chinese Academy of Sciences has also developed a new type of ion skin. This new type of ion skin not only has the characteristics of the original ion skin, which can bear force and deform, but it is also super sensitive and can even self-repair when injured.

(Video source: provided by the author)

It is a man-made material, but it can repair itself like human skin? This sounds amazing! So how does the self-healing property of the new ion skin come about?

The key lies in the dynamic disulfide bonds introduced into the material. The dynamic disulfide bonds are always in a dynamic equilibrium of breaking and reorganizing. When a wound is formed, the materials on both sides of the wound are bonded again due to the breaking and reorganization of the disulfide bonds near the wound. In this way, the self-healing of "human-like" skin can be achieved.

This new type of ionic skin is not only self-healing, but also super-sensitive! It simulates the ion signal transmission system similar to biological tactile cells, controls the distribution of ions inside the ionic conductor according to the change of force, and maximizes the tactile perception.

It sounds like the principle of self-healing is simple. Does it mean that the faster the healing, the better?

Although the researchers' goal is to develop self-healing ionic skin, this new material heals too quickly (not in Versailles), which has caused some minor trouble for the researchers.

During the development of this material, the self-healing behavior of the wound needed to be observed under a microscope. After each cut, various parameters had to be reset, and the self-healing speed of this material was too fast, causing researchers to always miss some important details. In the end, they had to improve the test equipment to get the video of the complete self-healing process below.

(Video source: provided by the author)

Conclusion

Ionic skin can mimic the structure and properties of human skin and has the ability to self-heal, which means it can be used to monitor human health and treat certain diseases. At the same time, the sensitivity of ionic skin to force also provides new possibilities for the development of human-machine interface devices.

Although the materials and manufacturing processes of ionic skin are not mature enough, we believe that in future research, ionic skin technology will be more widely used and further improved. In short, the research on ionic skin will promote the interaction and cooperation between humans and robots, and will also provide more intelligent and effective protection for human health.

References:

[1] https://www.nature.com/articles/s41467-022-35434-8

Editor: Guo Yaxin