In this graphic, a compression sleeve is turned into a biosensor that measures electrical impulses generated from muscle movement. Shown is the measurement of electrical activity picked up by the sleeve when a fist is made. (Credit: Huanan Zhang/University of Utah)

A new process turns clothing fabric into biosensors that measure a muscle’s electrical activity as it is worn. The researchers devised a method of taking ordinary textile made of a cotton/polyester blend and turning the fabric into sensors that measure electrical impulses generated from muscle movement.

The transformed fabric could become a much better solution in measuring muscle activity for physical rehabilitation or for other medical applications. Ordinarily, current bioelectrical sensor technology in which they tape sensors with wires to the skin can sometimes be ineffective, uncomfortable, expensive, and costly to manufacture.

The process involves depositing a microscopic layer of silver over a piece of fabric to make the material conductive and therefore receive the electrical signal from the muscle. But having just a layer of silver is a problem since the metal can be somewhat toxic when in prolonged contact with the skin. So, the researchers also deposit a second microscopic layer of gold, which is non-toxic to the touch. The gold not only protects the skin from the silver, but it also enhances the electrical signal.

The silver layer is applied to the fabric in a process similar to screen printing a graphic onto a T-shirt, and it’s applied to just the areas of the clothing that touch the muscle being measured. Then the gold layer is deposited by an electrochemical method. The patches of sensors are then attached to wires and a portable electromyography (EMG) device that measures muscle contractions.