Nanomagnet Patch Measures Muscle Movements

Researchers at UCLA have developed a wearable patch that can measure muscle movements in underlying tissues. The patch contains nanomagnets, and movements in underlying muscles can deform the resulting magnetic fields, creating an electric current. This both provides a readable signal for the system, and also means that the system is self-powered and does not require a battery. The rubbery patch is approximately the size of two postage stamps, and can be inexpensively made using a sewing machine. The system wirelessly transmits its movement data to a smartphone, and is water-resistant, helping it to stay functional even if the wearer is sweating heavily. The researchers hope that the technology will be useful in assessing muscle injuries and in developing personalized physical rehabilitation programs for patients.

A wearable that can pick up small vibrations and movements from underlying tissues has many potential applications, from assessing mobility and musculoskeletal injuries, to measuring heart and breathing rates. This technology is the latest creation of these UCLA scientists, who turned to magnets to create a completely self-powered wearable that can very sensitively take such measurements.

“Our device is very sensitive to biomechanical pressure,” said Jun Chen, one of the lead developers of the new patch. “The device converts muscle activities into quantifiable, high-fidelity electrical signals that are sent wirelessly to phone apps. This demonstrates the potential for personalized physical therapies and improving the rehabilitation of muscle injuries.”

The small patch is entirely self-powered, using changes in the positions of its enclosed magnets caused by muscle movements to generate electricity through changes in magnetic flux, in a phenomenon called electromagnetic induction. “Another highlight of the device is its self-powering properties,” said Chen. “The ability to convert biomechanical force to electricity means the device is also a generator. This eliminates the need for bulky, heavy, and rigid battery packs usually needed in wearable electronic designs.”

So far, the technology has been shown to be very sensitive. The researchers have tested it with human volunteers in different parts of the body, and have been able to measure throat movements associated with swallowing, ankle movements during walking, and when placed on the wrist the patch could measure someone’s pulse.

“We’ve tested the device for cardiovascular monitoring and respiration monitoring as well,” said Chen. “One day, we may be able to reinvent or replace current systems, such as EKGs, that require external power sources, and make them less bulky and more wearable.”

Study in journal Matter: A textile magnetoelastic patch for self-powered personalized muscle physiotherapy

Via: Cell Press