Human skin contains mechanoreceptors, which can detect something as subtle as the weight of a butterfly, as well as heat or cold from a nearby item. However, for persons who have prosthetic limbs, these sensations, whether positive or negative, are lost.
Researchers have discovered a means to assist amputees regain these sensations through electronic skin. The Bao Research Group at Stanford University has created a soft, flexible electronic skin (e-skin) that can simulate the process that causes a finger or toe to react and walk away when poked or touched by a heated surface. “This current e-skin really has all the attributes that we have been dreaming about,” says chemical engineer Zhenan Bao of Stanford University. “We have been talking about it for a long time.”
This revolutionary soft “e-skin” can directly transfer electrical signals to the wearer’s brain, allowing them to ‘feel’ pressure, strain, or temperature changes
According to Nature, this approach could lead to the production of a covering for prosthetic limbs. The nicest thing about this revolutionary soft “e-skin” is that it can directly transfer electrical signals to the wearer’s brain, allowing them to ‘feel’ pressure, strain, or temperature changes. Unlike past attempts, this new e-skin employs soft integrated circuits to translate sensory data like pressure and temperature into electrical signals resembling nerve impulses. The idea is to incorporate this technology into prosthetic limbs to provide sensory feedback and increase amputee control. The newly designed electronic skin was tested on a rat in an experiment. The e-skin was linked to the rat’s somatosensory cortex, which is the area of the brain involved in processing physical sensations.
When the electronic skin was touched, it produced an electrical signal that was sent to the brain. The signal was then routed through an artificial synapse to the rat’s sciatic nerve in its leg, causing the limb to twitch. According to Bao, they intend to design a less invasive device that will not require brain implantation in the future.
“We envision that for people who lost their limbs, we don’t have to implant into the brain,” she said as per Nature. “We could have an implant in the peripheral nervous system.” The current version of the e-skin is tethered to an external power source, but the researchers plan to produce a wireless gadget in the future. “This new e-skin runs on just 5 volts and can detect stimuli similar to real skin,” said Weichen Wang, the paper’s first author and a Ph.D. candidate in Bao’s lab.