Researchers Make a Smiling Robotic Face From Living Skin

The team designed a new way for their lab-grown skin to adhere to the robot’s face, in a creation that could help produce soft robots or train plastic surgeons

A pink, slimy smiling robot face on a dish
The face's novel anchors—holes filled with gel—allow the skin to stretch into a smile without damaging itself. Takeuchi et al., Cell Reports Physical Science, 2024, CC-BY-ND

Using living skin, scientists have made a robotic face that can stretch its features into a smile.

In a new paper published Tuesday in the journal Cell Reports Physical Science, researchers describe a novel method for attaching the lab-engineered skin to the robot’s face. The findings not only mark an advancement in robot facial technology—they could also have implications for the cosmetics industry and orthopedic surgery.

“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,” Shoji Takeuchi, a scientist at the University of Tokyo who led the research, says in a statement from the university.

One motivation for developing skin covers for robotic faces is that living skin can heal itself. Non-living skin on robots can suffer lasting scratches or other damage.

The research team had previously developed a finger-shaped robot cloaked in engineered skin tissue grown in the lab. This skin covering was able to repair itself. But faces, with their many contours, are more challenging surfaces to work with.

To create a face, the researchers needed a better way to bond the skin to the surface below. Previous research had relied on attachments like anchors and hooks, but these could cause damage to the skin when the face is moving.

With their study, the researchers introduced a new innovation: v-shaped holes in the robot’s face, meant to help hold the skin in place. Essentially, the design functions like skin ligaments, which lie below the external skin tissue in animals, giving it strength and structure.

They filled the holes with a collagen gel and added a water vapor-based plasma treatment that helped the gel, which is viscous, to cling to the underlying material. This could bind to the skin on top, the gel serving as anchors for the tissue.

This innovation “presents an interesting new way” to attach a soft, skin-like material to a rigid surface, Krishna Manaswi Digumarti, a soft robotics researcher at the Queensland University of Technology in Australia who was not involved with the study, tells Axios’ Rebecca Falconer.

“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 says in the statement.

The robotic face can be made to perform a realistic, if not creepy, smile before returning to its original shape. The researchers also attached the living skin to a stationary 3D facial mold using the same v-shaped perforations.

side-by-side images: at the right, the pink smiling face; at the left, an orange skin stuck to a mannequin-like human head
The team attached their living skin to the moving robot (right) and a stationary 3D facial mold (left). Takeuchi et al., Cell Reports Physical Science, 2024, CC-BY-ND

Digumarti tells Axios he would have liked to see a test of the material’s durability over time. “Is there any wear and tear at the anchors?” he says to the publication. “Does it peel off after 1,000 smiles, or can it last a million smiles?”

Regardless, the skin still must pass other hurdles before it can be used practically with robots.

“The lack of sensing functions and the absence of blood vessels to supply nutrients and moisture means it cannot survive long in the air,” Michio Kawai, a co-author of the study and bioengineer at Harvard University, tells New Scientist’s James Woodford. “To address these issues, incorporating neural mechanisms and perfusion channels into the skin tissue is the current challenge.”

Takeuchi tells Live Science’s Rory Bathgate that “improving the mechanical strength of the skin to match that of natural human skin is crucial. This involves optimizing the collagen structure and concentration within the cultured skin.”

“Another important challenge is creating human-like expressions by integrating sophisticated actuators, or muscles, inside the robot,” Takeuchi adds in the statement.

Beyond the implications for soft robotics, the team hopes the model can be used to improve scientists’ understanding of wrinkle formation—or as a tool to train plastic surgeons. The robotic face could also prove useful in research into skin aging, cosmetics, surgical procedures and more, researchers say.

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