Made in Japan, a robotic finger entirely covered with 'living' human skin: elastic and water-repellent, it is even capable of regenerating itself to repair any wounds with the help of a collagen patch.
The result, which represents a first step towards increasingly human robots, is published in the journal Matter by researchers from the University of Tokyo.
"The finger looks a little 'sweaty' just outside the culture medium," says Shoji Takeuchi, one of the study authors.
"Since the finger is powered by an electric motor, it is interesting to hear its noises in harmony with a finger that seems real."
Until now, the skin of robots has been made of silicone, a material that does not perfectly reproduce the finer texture of the skin or its specific functions.
Various attempts have been made to produce 'sheets' of living skin with which to cover robots, but have had little success due to the difficulty of adapting them to dynamic structures and irregular surfaces such as those of robots.
The Japanese group therefore tried a different approach, immersing the robotic finger in a solution made of collagen and human connective tissue cells (fibroblasts).
Once this mixture was attached to the finger, like a kind of primer, it formed a uniform base on which another layer of epidermal cells (the keratinocytes) was deposited which gave the skin of the robotic finger the same consistency of human skin and even its own ability to make a barrier by retaining moisture.
The skin thus obtained is sufficiently elastic to remain adherent to the robotic finger and adapt to its movements: in the event of an injury it can also self-repair, with the help of a collagen-based dressing.
It is obviously more delicate than natural skin and in order to survive it needs a system that supplies nutrients and removes waste products by mimicking the function of blood vessels.
However, researchers are already working to solve these problems and equip the skin with new elements, such as sensory neurons, hair follicles, nails and sweat glands.