Researchers want to create humanoid robots with human skin

Artificial leather covered in sensors was already giving robots rudimentary senses of heat or touch. Thin casings are mostly made of silicone-based plastic. Japanese material researchers have now gone one step further and grown skin from living cells. In Mater magazine, they describe how they were able to equip a robotic finger with this waterproof and self-healing skin. Scientists see possible applications in human-like robots that, thanks to electronic skin, are better able to mimic human facial expressions than plastic shells.

“This work is a first step towards robotics that can be completely covered with live skin,” says Shuji Takeuchi of the University of Tokyo. The basis of robotic skin is a process by which flat pieces of skin can actually be grown in the laboratory. However, it cannot be transferred directly to the robot’s finger. So, Takeuchi and his colleagues used a small rubber hose, which they slipped over a three-part robotic finger. In this tube they filled a nutrient solution with the structural protein collagen and living fibroblasts – the most important skin cells in the connective tissue.

Two weeks for robotic finger reproduction

After a few days, a closed skin formed that tightly stuck to the robot’s finger. In the second step, they added another type of cell, keratinocytes. In more than 90 percent, these skin cells are the most common cell type in human epidermis and produce the stable keratinocyte. After another two weeks of breeding, the robot’s finger can be completely covered with stable, waterproof skin. This withstood dozens of bending motions. If cracks appear, they can be closed again with a special plaster.

However, this robot skin did not last more than a few days. If the skin dries up, it loses its elasticity especially quickly and tears when you move your fingers. The Takeuchi team wants to solve this problem in further tests, for example by using rock channels to prevent the robot’s skin from drying out. In addition, tried and tested sensors for tactile and temperature sensations can be added in the future.