Washable Fabric Measures Electrical Activity of Muscles

  • April 05, 2022

The fabric contains a network of silver flakes and gold nanoparticles that provide conductivity and allow electrical signals to be measured in high fidelity using a portable electromyography (EMG) device.  Physical rehabilitation is a cornerstone of recovery from a variety of illnesses and injuries, but obtaining hard EMG data on muscle activity typically requires attaching wires and patches to the skin.  These patches can be uncomfortable and expensive, the wires inconvenient, and such systems only provide data from small areas of the body at any one time.

Imagine if our clothes could make such measurements instead. Granted, such clothing would need to make contact with the skin, and therefore be skintight, but many garments that people use for exercise or rehabilitation would fit that description already.  This latest technology brings such clothing a little closer to reality.  “This new method can enable clinicians to collect a muscle’s long-term electrical signals with more precision,” said Huanan Zhang, a Researcher involved in the study, in a University of Utah announcement.  “And we can get a better understanding of a patient’s progress and therefore their therapeutic outcomes over time.”

The system consists of ordinary fabric (a cotton/polyester blend) onto which the researchers deposit silver flakes using a screen-printing method.  The flakes are placed onto areas of the clothing that are intended to touch the muscles being assessed.  However, silver can be toxic and can irritate the skin, and so to address this, the researchers covered the silver with a layer of gold nanoparticles using an electrochemical deposition method.  The gold helps to improve the biocompatibility of the material and also enhances the electrical signal that can be recorded.  “The silver layer provides a baseline conductivity, but the gold on top improves the signal and the biocompatibility, and it helps reduces the cost of manufacturing pure gold devices,” said Zhang.

The material has proven to be very robust, and the University of Utah researchers report that they put the clothing through 15 washes and it still maintained its ability to measure muscle electrical activity.  The team hopes to upgrade the system in the future, and allow its integration with a smartwatch or smartphone to provide a convenient way to display the data coming from the clothes.

REFERENCE:  Med Gadget; 17 NOV 2021; Conn Hastings

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