Scientists at Stanford University have developed a way for those who have lost limbs to effectively “feel” through their prosthetics. Detailed in Science Magazine this week, researchers designed flexible organic circuits with specialized pressure sensors that can convert touch into digital signals that correspond to the amount of force applied. The synthetic skin, which the team has put on a robotic hand for experimentation, can distinguish a light touch from a firm handshake.
At first, the researchers struggled to imitate the sensitivity of human skin, since we can feel things as subtle as a light breeze. But after cycling through many different materials, the team settled on carbon nanotubes molded into pyramidal microstructures, as it seemed to be responsive to the broadest range of pressures.
“Our skin provides us with a flexible waterproof barrier, but it also contains a sensor array that feels the world around us. This array provides feedback and helps us to avoid a hot object or increase the strength of our grip on an object that may be slipping away,” wrote researcher Benjamin C.K. Tee, Zhenan Bao and their colleagues in the report.
In an interview, Bao, explained that the applications of this technology could begin with very simple “skin-like sensors for wearable health monitoring applications.” before moving on to working with prosthetics to allow people with artificial limbs to experience sensation again.
“Our devices can be mounted on skin like a piece of bandage and measure vital signs, such as heart rate and blood pressure,” she said, adding that the technology could even lend itself to robotics in the future, giving AI’s the ability to actually feel.
In another experiment with the material, the team found that applying some specially engineered proteins to part of a mouse’s brain known as the somatosensory cortex (the main sensory receptive area for touch) would make the mouse’s neurons fire at the same time as the digital stimulation pulse.
“These results indicate that the system may be compatible with other fast-spiking neurons, including peripheral nerves,” they said.