Robots keep getting creepier

• Researchers unveiled a smiling humanoid robot with lab-grown, self-healing skin.
• The team from the University of Tokyo used collagen gel to bond living skin tissue to 3D models.
• The researchers said it could benefit the cosmetics industry and help train plastic surgeons.

It's not just nuts and bolts keeping robots together — now they can be made with living skin. Skin that can be made to smile.

Researchers at the University of Tokyo revealed on Tuesday a rather unsettling humanoid robot covered with lab-grown skin cells. The team said it was able to mimic human skin ligaments by bonding skin tissue to perforated 3D facial models and 2D robots.

The team hopes the advancement will be useful "in the cosmetics industry and to help train plastic surgeons," according to a press release.

While the development could prove helpful, some people online reacted to the robot's fleshy skin and facial movements with jokes or said they found it disturbing. One user on X wrote, "You will live to see man-made horrors beyond your comprehension," while another said, "We don't want this. Nobody wants this. Stop it."

Unlike other robot materials used as skin, the method of using biological skin grants these robots self-healing capabilities that don't require triggers such as heat or pressure, the researchers said.

"Biological skin repairs minor lacerations as ours does, and nerves and other skin organs can be added for use in sensing and so on," said Professor Shoji Takeuchi, lead researcher for the study.

Other techniques, which require mini anchors or hooks, are often limited by the types of surfaces that can be used and could be damaged, the researchers said.

However, by using a "special collagen gel for adhesion," researchers were able to apply the skin to any surface, even curving or moving ones — like a smiling robot.

"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," Takeuchi said.

The team also hopes to create a thicker and more realistic skin by "incorporating sweat glands, sebaceous glands, pores, blood vessels, fat and nerves." Takeuchi said that creating humanlike expressions is another significant challenge they hope to tackle by incorporating actuators, which would act as muscles, into the robots.

This is just the latest development in humanoid robotics, which, sometimes disconcertingly, feature designs that mimic the look or functionality of people — sometimes falling into the uncanny valley.

Tesla is in the works of developing its Optimus robot, which CEO Elon Musk hopes people will regard "sort of as a friend." Other bots operate on all fours, like Boston Dynamic's four-legged robotic police dog.

While you probably don't have to worry about seeing living skin on a production robot anytime soon, the University of Tokyo researchers have at least proven that it's possible — even if that means a bit of nightmare fuel for the rest of us along the way.