Smiling robot face is made from living human skin cells

A smiling face made from living human skin could one day be attached to a humanoid robot, allowing machines to emote and communicate in a more life-like way, say researchers. Its wrinkles could also prove useful for the cosmetics industry.

The living tissue is a cultured mix of human skin cells grown in a collagen scaffold and placed on top of a 3D-printed resin base. Unlike previous similar experiments, the skin also contains the equivalent of the ligaments that, in humans and other animals, are buried in the layer of tissue beneath the skin, holding it in place and giving it incredible strength and flexibility.

Michio Kawai at Harvard University and his colleagues call these ligament equivalents “perforation-type anchors” because they were created by perforating the robot’s resin base and allowing tiny v-shaped cavities to fill with living tissue. This, in turn, helps the robot skin stay in place.

The team put the skin on a smiling robotic face, a few centimetres wide, which is moved by rods connected to the base. It was also attached to a similarly sized 3D shape in the form of a human head (see below), but this couldn’t move.

“As the development of AI technology and other advancements expand the roles required of robots, the functions required of robot skin are also beginning to change,” says Kawai, adding that a human-like skin could help robots communicate with people better.

The work could also have surprising benefits for the cosmetics industry. In an experiment, the researchers made the small robot face smile for one month, finding they could replicate the formation of expression wrinkles in the skin, says Kawai.

“Being able to recreate wrinkle formation on a palm-sized laboratory chip can simultaneously be used to test new cosmetics and skincare products that aim to prevent, delay or improve wrinkle formation,” says Kawai, who performed the work while at the University of Tokyo.

Of course, the skin still lacks some of the functions and durability of real skin, says Kawai.

“The lack of sensing functions and the absence of blood vessels to supply nutrients and moisture means it cannot survive long in the air,” he says. “To address these issues, incorporating neural mechanisms and perfusion channels into the skin tissue is the current challenge.”