Robotic grin crafted from living human skin cells

Researchers say smiles made from living human skin could one day be attached to humanoid robots, allowing the machines to emote and communicate in a more lifelike way – and the wrinkles could even be useful for the cosmetics industry.

The living tissue is a mixture of human skin cells grown on a collagen scaffold, then placed on a 3D-printed resin base. Unlike previous similar experiments, this skin also contains the equivalent of ligaments, which are embedded in the layers of tissue beneath the skin of humans and other animals and hold the skin in place, giving it incredible strength and flexibility.

Michio Kawai The Harvard researchers call their ligament equivalents “perforated anchors” because they were made by drilling holes in the robot's plastic base and filling the tiny V-shaped cavities with tissue, which helps the robot's skin stay in place.

The team attached the skin to a smiling robotic face a few centimeters wide, which could be moved by rods attached to a base, and to a similarly sized 3D shape in the shape of a human head (see below), which could not be moved.

“As the roles required of robots expand due to developments in AI technology and other factors, the functions required of robot skin are also starting to change,” Kawai said, adding that having human-like skin could make communication between robots and humans smoother.

The research could also have unexpected benefits for the cosmetics industry: In tests, the researchers made the tiny robot's face laugh for a month and found that they could replicate the formation of expression wrinkles on the skin, Kawai says.

“If we can reproduce wrinkle formation on a palm-sized research chip, it could also be used to test new cosmetics and skincare products aimed at preventing, delaying or improving wrinkle formation,” said Kawai, who conducted the research while at the University of Tokyo.

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

“They have no sensing capabilities and no blood vessels to provide them with nutrients and water, so they cannot survive long in air,” he says. “To address these issues, our current challenge is to incorporate neural mechanisms and perfusion pathways into the skin tissue.”