Japanese scientists develop self-healing skin for robots

By Stephen Beech via SWNS

Terminator-style self-healing robots are a major step nearer reality.

Japanese scientists have found a way to bind engineered skin tissue to humanoid robots.

They say the breakthrough brings with it potential benefits to robotic platforms including increased mobility as well as self-healing abilities, embedded sensing capabilities and an increasingly lifelike appearance.

Taking inspiration from human skin ligaments, the team, led by Professor Shoji Takeuchi of the University of Tokyo, included special perforations in a robot face, which helped a layer of skin take hold.

The team says their research, published in the journal Cell Reports Physical Science, could also be useful in the cosmetics industry and to help train plastic surgeons.

Takeuchi is a pioneer in the field of biohybrid robotics, where biology and mechanical engineering meet.

So far, his lab, the Biohybrid Systems Laboratory, has created mini robots that walk using biological muscle tissue, 3D-printed lab-grown meat and engineered skin that can heal.

It was during that research Takeuchi felt the need to take the idea of robotic skin further to improve its properties and capabilities.

He said: “During previous research on a finger-shaped robot covered in engineered skin tissue we grew in our lab, I felt the need for better adhesion between the robotic features and the subcutaneous structure of the skin.

“By mimicking human skin-ligament structures and by using specially made V-shaped perforations in solid materials, we found a way to bind skin to complex structures.

"The natural flexibility of the skin and the strong method of adhesion mean the skin can move with the mechanical components of the robot without tearing or peeling away.”

Previous methods to attach skin tissue to solid surfaces involved methods such as mini anchors or hooks, but these limited the kinds of surfaces that could receive skin coatings and could cause damage during motion.

By carefully engineering small perforations instead, Takeuchi says essentially any shape of the surface can have skin applied to it.

The trick the team employed was to use a special collagen gel for adhesion, which is naturally viscous so difficult to feed into the minuscule perforations.

But using a common technique for plastic adhesion called plasma treatment, they managed to coax the collagen into the fine structures of the perforations while also holding the skin close to the surface in question.

Takeuchi said: “Manipulating soft, wet biological tissues during the development process is much harder than people outside the field might think.

"For instance, if sterility is not maintained, bacteria can enter and the tissue will die.

“However, now that we can do this, living skin can bring a range of new abilities to robots.

"Self-healing is a big deal - some chemical-based materials can be made to heal themselves, but they require triggers such as heat, pressure or other signals, and they also do not proliferate like cells.

"Biological skin repairs minor lacerations as ours does, and nerves and other skin organs can be added for use in sensing and so on.”

Takeuchi and his team have a goal in mind for the application that could help in several areas of medical research.

The idea of an organ-on-a-chip is not especially new and finds use in things such as drug development, but something like a face-on-a-chip could be useful in research into skin aging, cosmetics, surgical procedures, plastic surgery and more.

Takeuchi says that if sensors can be embedded, robots may be endowed with better environmental awareness and improved interactive capabilities.

He said: “In this study, we managed to replicate human appearance to some extent by creating a face with the same surface material and structure as humans.

“Additionally, through this research, we identified new challenges, such as the necessity for surface wrinkles and a thicker epidermis to achieve a more humanlike appearance."

Takeuchi added: "We believe that creating a thicker and more realistic skin can be achieved by incorporating sweat glands, sebaceous glands, pores, blood vessels, fat and nerves.

"Of course, movement is also a crucial factor, not just the material, so another important challenge is creating humanlike expressions by integrating sophisticated actuators, or muscles, inside the robot.

"Creating robots that can heal themselves, sense their environment more accurately and perform tasks with human-like dexterity is incredibly motivating.”