In the movies, we always see AI systems and robots that are eerily close to human form. Even though, in reality, it's a long way off, the world of technology makes advancements every day that put us so much closer to that happening.

Scientists from Stanford University have created a type of synthetic skin that contains electronic mechanoreceptors. These are what give humans the sense of touch. The receptors are embedded in our skin, and when they feel pressure they send electrical signals to the brain, creating the sense of touch.

With the synthetic skin that includes these receptors, scientists could essentially give robots the sense of touch. Perhaps more promising is the fact that they could include them in prosthetics, allowing those who have lost their limbs to feel once again.

How Does It Work?

The skin is designed with multiple layers. Each layer serves a specific purpose when it comes to generating sensory output. One layer is an ink jet-printed organic electrical circuit, which is remarkably thin and will handle the electrical signal output. Another layer, which lays on top of that, is designed to work as a pressure-sensitive area. On that pressure sensitive layer is a series of minuscule, rubber pyramids. Within each of those pyramids is a carbon nanotube which can act as a conductor.

As soon as pressure is applied to the synthetic skin, it pushes the sensory layer down, causing the nanotubes to move near each other, which boosts conductivity and sends more electrical signals to the organic layer. In turn, this information can be used to discern the amount of pressure that’s being applied.

It’s similar to how different types of load cells work. Matt Borzage, the founding partner of SynTouch, described a nearly identical system to Zdnet—one that’s used to measure weight.

“Classically, pressure sensing has been performed with a strain gauge, which is an electronic element that deforms slightly when force is applied. If you have a digital bathroom scale, it uses a strain gauge to tell you how much you weigh.”

If the synthetic skin were to be implemented into a robot, a computer would need to assess the incoming sensory information to let it know the amount of pressure being applied to its skin.

However, for those wearing prosthetics, or amputees, the electrical signals would be sent to their brains, allowing them to feel with their limbs once again.

Is It Possible for Amputees to “Feel” Again?

Believe it or not, several advancements have put us that much closer to connecting synthetic skin from prosthetics to the wearer’s brain. By using a process called optogenetics, which calls for neurons to be activated by pulses of light, scientists have been able to successfully stimulate Vitro mouse brain cells from electrical signals sent by their skin.

Of course, there were some setbacks. For instance, the proteins that are usually used in optogenetics to register signals sent by skin wouldn’t stimulate for the appropriate amount of time. This meant that the scientists had to engineer or generate new proteins in their place.

As you can see from the description, it’s also not quite at the human testing phase, which means it will be a long while before they attempt anything like this with human amputees.

In the meantime, the team behind the synthetic skin, which includes professor Zhenan Bao, will be working to improve it. They plan on doing several things with it next, such as mimicking the elasticity of real human skin, and finding a way to implement the sense of heat or cold.

They’re not the only team working on synthetic skin, however. There are also scientists from Georgia Tech, the University of Southern California, MIT (News - Alert), and several other institutions working on similar tech projects.

With so much talent concentrating on this fascinating problem, it won’t be long before there are even more advancements in this exciting scientific field.