Bioelectronic device tested for wearables

New wearable device capable of recording the electrical activity of the heart and muscles, as well as delivering therapeutic electrical and thermal stimulations. It is suitable for flexible joints, like the wrist, and allows reliable heat transfer even when the wrist is flexed or extended. (c) Institute for Basic Science

Researchers at the Institute of Basic Science, South Korea, have developed a wearable and implantable device, that measures electrophysiological signals and applies electrical and thermal stimulations. The bioelectonic device provides information on muscle and cardiac dysfunctions, and thus could be implemented for pain relief, rehabilitation, and prosthetic motor control.

Thanks to its softness, elasticity and stretchability, it can follow the contours of flexible joints, such as the wrist. It simultaneously monitored electromyogram (EMG) signals, and delivered electrical and/or thermal stimulations that could be employed in therapeutic applications.

Bioelectronic mesh

The research team has also produced a customized large mesh that fits the lower part of a swine heart. Wrapped around the heart, the implant can read signals from the entire organ to identify possible lesions and help recovery. For example, it was able to register the change of ECG signal caused by an acute heart attack. The mesh is stable during repetitive heart movements and does not interfere with the heart’s pumping activity.

“Although various soft cardiac devices have been reported for the rat heart. This study on pigs can approximate human physiology more accurately,” says CHOI Suji, first co-author of the study. “We aim to study heart diseases, and stimulate the heart more effectively by synchronizing cardiac pumping activity.”

The mesh implanted around a pig’s heart was able to record cardiac activity in multiple points. The ECG produced by the device detected an abnormality (ST elevation) caused by an acute heart attack (ischemia). (c) Institute for Basic Science

This stretchable and conductive patch is created by gold-coated silver nanowires mixed with a type of rubber, called polystyrene-butadiene-styrene (SBS). Conventional silver wire-based conductive rubbers have had limited biomedical applications because silver is toxic to the body.The gold sheath prevents both silver’s leaching, and corrosion caused by air and biological fluids, such as sweat. “We took advantage of silver’s high conductivity, SBS’ stretchability, and gold’s high biocompatibility,” explains HYEON Taeghwan, director of the Center and corresponding co-author. “Finding the right proportion of each material was the key to success.”

Source: Institute for Basic Science