People using prosthetic limbs may one day be able to feel pressure, temperature and even differences between surfaces thanks to a new type of electronic skin developed by researchers at Washington State University.
The technology, described in Cell Reports Physical Science, uses a network of tiny sensors designed to fit closely around prosthetic limbs.
According to the researchers, the system can detect sensations at a resolution about 10 times finer than current commercial glove sensors.
Restoring some sense of touch is an important goal in prosthetic technology.
Without sensory feedback, people using artificial limbs often have to rely heavily on vision to judge how firmly they are holding something or what kind of surface they are touching.
Even partial sensation could make everyday tasks easier and more natural.
Electronic skins, or e-skins, already exist, but current systems have several limitations. They can be expensive, provide relatively low sensing resolution and cover only small areas. Customizing them to fit complicated body shapes can also reduce their sensing performance.
The Washington State University team wanted to create an electronic skin that could be both highly sensitive and individually fitted to a person’s prosthetic limb.
Their solution uses a “scan-model-print” process. First, a scanner captures the exact shape of the prosthetic. Researchers then create a digital model and determine where the sensors should be positioned. Finally, the system is manufactured to match the prosthetic’s unique shape.
The individual sensor modules contain both pressure and temperature sensors in thin layers. Together, they can collect detailed information across flat and curved surfaces. This allows the system to recognize characteristics such as surface texture and material properties in a way that more closely resembles human skin.
The modules are also designed to connect together rather than being attached with adhesives. The researchers compare the approach to snapping Lego bricks together. This could make the electronic skin easier to assemble, repair and customize.
Another advantage is relatively simple manufacturing. The team primarily uses 3D printing and laser cutting, technologies that are already widely available. The researchers believe this could eventually make the system cheaper and easier to produce than some existing medical-grade electronic skins.
However, detecting touch is only part of the challenge. The ultimate goal is to allow a person to actually experience the sensations detected by the artificial skin.
The researchers are now developing an actuator that could translate information from the sensors into stimulation signals. These signals would then activate nearby nerves, potentially allowing an amputee to sense what the prosthetic limb is touching.
The team has already submitted an invention disclosure for a provisional patent and plans to continue developing the technology.
If successful, the system could eventually lead to more personalized prosthetic limbs that do more than replace movement.
By combining advanced sensors with nerve stimulation, future prosthetics may come much closer to restoring the missing sense of touch.
