Screen-Printing Tiny Layers of Silver and Gold Turn Common Fabrics Into Sensitive EMG Sensors

Researchers at the University of Utah and Gyeongsang National University have developed a way to print electromyography (EMG) sensors directly onto clothing — dramatically reducing their cost while improving the quality of the signal.

"This work explores the possibility of combining screen printing and electrodeposition techniques to produce a biostable nanocomposite-based EMG biosensor on textile," the team writes in the abstract to the paper. "Screen printing was selected to fabricate conductive fabrics that would ultimately be a highly durable textile-based sensor."

Initially, the researchers began by using screen-printing techniques to place silver paste directly onto fabric — but while silver is a good conductor it is also mildly toxic, making it a poor choice for prolonged skin contact. The solution: A layer of gold nanoparticles over the top, which insulates the silver from the skin will maintaining conductivity. Because both silver and gold layers are so thin, the cost is kept low — yet performance proved impressive.

"Every time your finger moves, the potential of the body, of the muscle, changes. So, we are able to detect that difference in potential," Huanan Zhang, co-author of the paper, explains. "This work not only designs a wearable device, which has the convenience factor, but it also has great performance and is biocompatible."

The prototype wearable sensors developed during the project, a bicep sleeve and a glove, proved capable of tracking muscle movements during a range of exercises — and also withstood multiple washing cycles, suggesting that sensor-equipped clothing could be used every day.

"The study demonstrates," the researchers conclude, "that therefore this affordable approach can be used for scaling up the EMG monitoring."

The team's work has been published under open-access terms in the journal APL Materials.