Japanese scientists have taken us one step closer to human-like robots by implanting living human skin on robots, giving their fingers skin-like texture as well as water-repellent and self-healing capabilities.
While current silicone skin for robots can mimic human appearance, it falls short in delicate textures such as wrinkles and lacks skin-specific functions.
“The (new) finger looks slightly ‘sweaty’ straight out of the culture medium,” said first author Shoji Takeuchi, Professor at the University of Tokyo, Japan.
“Since the finger is driven by an electric motor, it is also interesting to hear the clicking sounds of the motor in harmony with a finger that looks just like a real one,” he added.
Takeuchi noted in the paper, which was published in the journal Matter, that in order to efficiently cover surfaces with skin cells, they developed a tissue moulding method to directly mould skin tissue around the robot, resulting in seamless skin coverage on a robotic finger.
The team began by immersing the robotic finger in a cylinder filled with a solution of collagen and human dermal fibroblasts, the two main components that make up the skin’s connective tissues.
Takeuchi attributes the study’s success to the collagen and fibroblast mixture’s natural shrinking tendency, which shrank and tightly conformed to the finger.
This layer, like paint primers, provided a uniform foundation for the next coat of cells — human epidermal keratinocytes — to adhere to. These cells constitute 90% of the skin’s outermost layer, giving the robot a skin-like texture and moisture-retaining barrier properties.
The crafted skin was strong and pliable enough to withstand the dynamic movements of the robotic finger curling and stretching.
When injured, the crafted skin could even self-heal like human skin using a collagen bandage that gradually morphed into the skin and withstood repeated joint movements.
“We are surprised by how well the skin tissue conforms to the robot’s surface,” said Takeuchi. “But this work is just the first step toward creating robots covered with living skin.”
The developed skin, on the other hand, is much weaker than natural skin and cannot survive for long without constant nutrient supply and waste removal.
Takeuchi and his colleagues intend to address these concerns by incorporating more sophisticated functional structures within the skin, such as sensory neurons, hair follicles, nails, and sweat glands.
“I think living skin is the ultimate solution to give robots the look and touch of living creatures since it is exactly the same material that covers animal bodies,” said Takeuchi.
