Since the first robot was made, researchers have struggled with ‘uncanny valley’, the feeling of being unsettled by something that looks almost human, but not entirely realistic. Well now, scientists have found a solution to this problem: simply slap some human skin on the bots.
Okay, that’s an oversimplification, but it isn’t actually that far off. A team comprising researchers from the University of Tokyo, Harvard University and the International Research Center for Neurointelligence has created a lifelike skin for robots using living human skin cells.
Their research was published in the journal Cell Reports Physical Science and could be a big step forward in robotics, in terms of making them look more human, and improving their durability and use in a large number of fields.
“It’s created by culturing skin cells obtained from excess skin tissue during surgeries, together with collagen tissue. In this study, we created skin tissue fixed to a device by solidifying the skin around a device with a perforation anchor structure,” says Michio Kawai, the lead author of the research.
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Originally, the team tried using tiny hooks to keep the skin attached to the face, but that was causing tears. Attempts in the past have used other techniques to secure the skin, but these often leave lumps, compromising the human-like appearance of the robots.
The ‘perforation anchor structure’ instead mimics how real skin works and achieves a much more natural look in the skin of the robot.
Human bodies contain a structure known as fascia. This is a thin casing of connective tissue that holds every organ, blood vessel, nerve fibre and muscle in place. The researchers attempted to recreate this, drilling holes into the robot and applying a collagen-based gel followed by the skin. The gel plugs the holes, keeping the skin in place.
So robot skin is now a possibility, but why on Earth are we doing it? “The primary goal here is to create a robot that can self-repair surface damages,” says Kawai. “As artificial intelligence develops, the functions required of robot skin are also beginning to change. To handle a wider range of tasks, robots have begun to evolve from rigid skin to soft robots over decades.”
Kawai highlights the need for robots to have a more lifelike appearance and functionality as they take on roles that involve communication and uncertain environments. Cultured skin is easy and affordable to repair, making it a viable option for long-term use on robots.
There are still obstacles to overcome, however. The main one being that the skin can’t be left out in the air for long because it doesn’t contain any blood vessels; the exposure causes the skin to dry out and die in a matter of hours.
“The next step will be to create a supply route for nutrients and moisture, similar to blood vessels, within the skin tissue to enable long-term use.” Another obstacle is that, while the skin is naturally flexible and the method of securing it to the robot is surprisingly strong (so it should stay in place without tearing or peeling away) it has to be handled with the utmost care.
“Manipulating soft, wet biological tissue during the development process is much harder than people might think,” says Shoji Takeuchi, biohybrid systems professor at the University of Tokyo. “If sterility is not maintained, bacteria can enter and the tissue will die.”
Takeuchi and his team have worked on a number of similar projects in the past, including skin that can heal, small robots with biological muscle tissue, and 3D printing lab-grown meat.
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In fact, the team previously worked on a piece of robotic skin a few years ago. Using a mix of collagen and human dermal fibroblasts, they made a skin solution. Dipping a robotic finger into the skin solution created a realistic human finger.
Through the process of developing these skin-covered robots, the team discovered a number of challenges. The necessity for wrinkles, for example, and thicker layers of skin to replicate human expression.
While the researchers were able to create a ‘smiling’ robot, there’s still a long way to go to fully replicate human skin. The team believes this comes down to the anatomic structures found in humans including glands, pores, blood vessels, fat and nerves.
In the past, other teams have been able to create sensors for robots to ‘feel’ pain and other sensations. As the technology of soft robotics improves, we’re slowly approaching a form of robot that can replicate the skin, feeling and expressions of humans.
While the primary focus is on the use of skin in robotics, the research could also benefit skin ageing, cosmetics and surgical procedures including plastic surgery. It could also be used as a training tool, offering surgeons the opportunity to work on real-skinned robots.
It will, however, be a while before this technology comes into common use. There are still problems with the skin and it has only been used for the purposes of demonstration in the published research paper.
About our experts
Michio Kawai is a PhD candidate at Harvard University studying Bioengineering. His work has been published in Cell Reports Physical Science, Heliyon, and Matter.
Shoji Takeuchi is a biohybrid systems professor at the University of Tokyo. His work has been published in Science Robotics, Nature Chemistry, and Nature Communications (to name a few journals).
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