Researchers at the University of St Andrews, Scotland, have developed a light-based sensor that can be used to control the movement of prosthetic limbs, according to research published online December 9 in the journal Advanced Materials.
Researchers shine light into muscle to detect instructions for prosthetic limbs. Research team member Olena Kulyk wears the sensor on her upper arm, next to the robot that it controls.
Photograph courtesy of the
University of St Andrews.
Professor Ifor Samuel, PhD, and Ashu Bansal, PhD, both with the university’s School of Physics and Astronomy, have developed a new class of wearable optical sensors with potential applications for medicine, rehabilitation, and sports. The team used plastic semiconductors to produce a wearable sensor of muscle contraction. The device consists of a light source and four photodetectors made from semiconducting polymers arranged and assembled as a flexible bandage. The technology works by shining light into fibrous muscle and observing how the light is scattered. When muscle is contracted the light is scattered less because the muscle fibers are farther apart. Sensors are then able to detect the changed scattering signals and relay the information, as photocurrents, to a robotic arm where the action is realized.
The discovery could begin a new era of low-cost disposable wearable optical sensors, relieving patients from risks associated with electrical-based sensors including electromagnetic interference, pain caused by sensing-needles, and immune responses.
“Wearable sensors are important for continuous monitoring of health and our approach offers the advantages of being noninvasive, lightweight, flexible, and simple to make,” Samuel said. “By using light we avoid needles that would be needed to make electrical contact.”
The team demonstrated the application of the muscle contraction sensor by showing that it could be used to control a robotic arm that mimicked the movement of a real arm.
Bansal added, “This sensor can distinguish different types of contractions and can add extra functionality to active prosthetics enabling natural movements of the limbs, which is not available with currently available techniques.”
