Even after significant advances in the industry, humanoid robots remain firmly in the uncanny valley. And while a Japanese team’s new lab-made skin may not diminish the creepiness of a bot, it could one day become a useful medical device for cosmetic surgery and other medical procedures.
As detailed in a study published June 25 in Cell reports natural sciencesengineers from the University of Tokyo have developed a method to attach bioengineered skin grown from human cells to any surface shape. Existing approaches often rely on miniature anchors and hooks to attach similar tissues to surfaces, limiting their usefulness and making them easily susceptible to damage during movement.
In this case, however, researchers created miniature V-shaped perforations in their lab-grown skin to make it extremely flexible, and then applied a collagen gel. Although the viscosity of the gel would normally prevent it from seeping into the small incisions, the engineers used a so-called water vapor plasma treatment commonly used during plastic bonding processes. This made the skin more hydrophilic, allowing the collagen to seep into the tissues and bond the skin to the underlying surface, much like ligaments.
“By mimicking human skin-ligament structures and using specially designed V-shaped perforations in solid materials, we have found a way to bond skin to complex structures,” said corresponding author and professor of mechanoinformatics Shoji Takeuichi said in a statement“The skin's natural flexibility and strong bonding method allow the skin to move with the robot's mechanical components without tearing or peeling.”
But even with the improved stickiness, that slimy sheen is more than just a little gross: It can be disastrous for lab-engineered skin.
“Manipulating soft, wet biological tissues during the development process is much more difficult than people outside the field might think. For example, if sterility is not maintained, bacteria can enter and the tissue will die,” Takeuichi continued. However, now that they can do this successfully, “living skin can offer a range of new capabilities to robots.”
[Related: Watch a robot hand only use its ‘skin’ to feel and grab objects.]
To demonstrate their new technique, the team attached their living skin layers to a 3D facial model of a human, as well as to a small 2D 'face' with robotic actuators. Not only did the skin adhere effectively to the round facial features of a human head, but it also resisted manipulation using the actuators, as they formed a rudimentary, smiling face.
By Takeuichi’s own admission, the smooth skin only managed to mimic human appearance to a certain extent, but that’s not the main point of their team’s design. Comparing their technique to creating an organ-on-a-chip, a future face-on-a-chip could open up new possibilities for research into skin aging, plastic and reconstructive surgery, and even cosmetics. Combined with embedded sensors, a new generation of robots could offer greater environmental awareness.
In the future, Takeuichi and his collaborators want to add the ability to develop surface wrinkles and a thicker epidermis to create a more human-like example. But if you think lab-grown robot skin is repulsive enough on its own, you better prepare yourself.
“We believe that creating thicker and more realistic skin can be achieved by integrating sweat glands, sebaceous glands, pores, blood vessels, fat and nerves,” Takeuichi said. Whether all of this is something a human or a robot would laugh at remains to be seen.
