Silicone skin, for instance, can’t create delicate nuances like flexible pores or wrinkles that come with age. It has a ceiling on how closely it can replicate the human organ. And Takeuchi also said other attempts to create human skin have had limited success because they require skilled artisans to cut and tailor sheets of lab-grown skin to fit them on a robot finger. “To efficiently cover surfaces with skin cells, we established a tissue molding method to directly mold skin tissue around the robot, which resulted in a seamless skin coverage on a robotic finger,” Takeuchi said. How to build humanoid robot skin Basically, the team took a standard robotic finger, then submerged it in a cylinder filled with a special solution that fostered the right conditions to grow living skin. This solution was filled with collagen, a protein that helps with skin elasticity and stretchiness, as well as what are called “human dermal fibroblasts.” These fibroblasts just refer to the skin cells that the researchers used. Together, the two components comprise traditional skin tissue — it’s the same kind of duo found with our own bodies. Next, the collagen and fibroblast mixture shrank around the robotic finger, tautly covering it like a skin primer of sorts. This was the first layer of skin. The second layer, by contrast, swapped the fibroblasts for a new type of cell line called human epidermal keratinocytes — that’s because these cells make up about 90% of the outermost layer of skin in our bodies. Finally, once the keratinocytes stuck to the fibroblast primer, the mechanism was pretty much complete. The robot finger had skin.