The combination of cultured cells and silicon could help future robots look more human with realistic skin elasticity. And they can smile just like us. Robots of the future could be wrapped in realistic skin that can regenerate the same way human skin heals, thanks to a new approach involving cultured skin cells.

Researchers say the skin will look more realistic thanks to a new way the skin attaches to the robot’s skeleton, as well as the ability to repair any cuts or scratches on its own. They published their findings June 25 in the journal Cell Reports Physical Science.

Roboticists have previously tried to solve the problem of artificial skin sagging on a metal frame by securing it with “anchors,” hooks or mushroom-like structures. This prevents the skin from sliding on the robot’s frame, but sticky structures can stick under the skin in lumps, distorting its human appearance.

In a new study, researchers proposed a method in which the robot’s skeleton includes small holes through which artificially grown skin can extend v-shaped hooks, known as “hole-type anchors.” It keeps the faux leather in place while providing a smooth and flexible surface.

We make the robot’s appearance more realistic

Artificial leather is applied to the work treated with water vapor plasma to make it hydrophilic, in other words, to attract liquid to the surface. This means the cultured skin gel is drawn deeper into the holes to adhere more tightly to the robot’s surface.

Artificial skin has long been touted as a way to make robots more human-like; cultured leather looks more realistic than synthetic materials such as latex. However, without the correct gluing approach, the fake skin may sag from the robot’s frame, which is a concern.

One of the main advantages of this new shell is that it allows robots to work alongside humans without experiencing excessive wear and tear. The team said minor tears or similar damage could be repaired without the need to manually repair the robots. However, they did not measure how quickly the artificial skin healed after damage.

In one demonstration, researchers recreated how a person’s skin changes when they smile. This involved attaching artificial skin to the robot’s face with a layer of silicone that slid underneath. This causes “puffed out cheeks” as the muscles at both corners of the mouth tighten and the skin also tightens. Thanks to the perforated mounting locations, the skin could fit seamlessly into the 3D shape of the face without protruding bolts or hooks.

The researchers also compared surface-applied artificial skin with and without perforation-based fasteners. On unanchored surfaces, the crust shrank 84.5% in seven days, while on surfaces with a 0.04 inch (1 millimeter) anchor, this rate was 33.6%. Shrinking the robot’s fairing will cause the fairing to separate from the robot’s internal frame, distorting its realistic appearance and possibly damaging the fairing layer. Skin on surfaces with larger 0.1-inch (3 mm) and 0.2-inch (5 mm) diameters lasted even longer, at 26.4% and 32.2%, respectively.

How to create humanoid androids

Shoji Takeuchi, a researcher at the University of Tokyo’s Institute of Industrial Sciences (IIS), told Live Science that several steps still need to be taken before robots can wear skin using the team’s methods.

“First, we need to improve the strength and durability of cultured skin when applied to robots, particularly by addressing issues related to nutrient and moisture supply,” he said. “This may include the development of integrated blood vessels or other perfusion systems in the skin.”

“Second, it is crucial to increase the mechanical strength of the skin to match that of natural human skin. This involves optimizing the structure and concentration of collagen in cultured skin.”

Takeuchi also noted that for artificial skin to be truly functional, it must eventually transmit sensory information such as temperature and touch to any robot wearing it, as well as being resistant to biofouling.

Research in this area could improve our understanding of how facial muscles convey emotion, which could lead to breakthroughs in surgery to treat conditions such as facial paralysis or expand the possibilities of cosmetic and orthopedic surgery, the scientists said. A better understanding of skin adhesion may also prevent the need for any V-holes in future studies.