In order for wearable devices to “disappear” into our daily lives, they must be flexible and conform to normal body movements. Standard metal wires are excellent at conducting electricity; while they typically are flexible to some degree, they tend to be unforgiving when it comes to stretching. As a result, many researchers are looking to novel materials such as graphene or conductive plastics to create flexible conductors that can stretch reliably.

Researchers at North Carolina State University have taken a different approach. By taking advantage of the flexible nature of metal traces, they have developed serpentine patterns that can “stretch” simply by bending the curved shapes. The scientists developed an ink that contains silver nanowires, and then use it to print the patterns onto flexible plastic substrates. The ink uses a non-toxic, water-soluble solvent, which can simply be washed off after the conductive traces have been printed. The result is an inexpensive conductor that can bend and stretch, and can easily be scaled for larger devices. The team has already created gloves that use the conductors as a means of heating the wearer’s hand, as well as a wearable electrode for cardiograms.

Advances such as this could lead to sensors and other wearable digital devices that are thin, flexible, and can change shape as a subject’s body moves. This technology could help us monitor our health and even deliver treatment automatically without having to think about it.