Stretchable Sensor Made from Chewing Gum, Carbon Nanotubes

A stretchable sensor made from chewing gum and carbon nanotubes could allow wearers the flexibility to monitor vital signs from some of the most bendable parts of their body.

Many conventional sensors that monitor body functions such as heart rate and sleep cycles are made from metal. That means they may stop working when they are twisted or pulled too much. For sensors to allow for the full range of a body’s bending and stretching, they require a high degree of elasticity. To meet that need, various researchers have tried developing sensors using stretchable plastics and silicones. But what they may have gained in flexibility, they often lost in sensitivity.

Malcolm Xing, assistant professor of engineering at the University of Manitoba, and his research team found what they say is a better solution. To make their sensor suppler, a team member chewed a typical piece of gum for 30 minutes, washed it with ethanol and let it sit overnight. A solution of carbon nanotubes, the sensing material, then was added. Simple pulling and folding coaxed the tubes to align properly.

Human finger-bending and head-turning tests showed the material could keep working with high sensitivity even when strained 530%. The sensor also could detect humidity changes, a feature that could be used to track breathing, which releases water vapor with every exhale.

Because the gum sensor can be patterned into various forms, the researchers say they believe it potentially has wide application in miniaturized sensors and biochips.