Graphene-Fed Silkworms Spell Hope for Future Material for Wearables

Technology > Material

Photo by: AlexanderAlUS via Wikimedia Commons

Today’s wearable body sensors are usually made with semiconductors and designed mainly to monitor health.  

High-tech apparel such as smart socks work by using strain sensors that measure the changes in force.  There is just one wrinkle that needs to be fixed:  The sensors lose a bit of its sensitivity as it is stretched.

Lately, scientists are turning to silk to develop more sensitive multi-purpose devices.  Silk is a natural material that is stronger than steel and more flexible than nylon but it is not a good conductor of electricity.

Dr. Yingying Zhang, who led the study, said, “Silk is the ideal material for fabricating sensors that are worn on the body.” He said silk sensors could be used as “an integrated wireless system that would allow doctors to more easily monitor patients remotely” for a quicker medical response.To solve this, researchers from Tsinghua University in China are feeding silkworms graphene -- a superb conductor made of ultra-light yet extremely strong material.  If successful, the silk produced could be used to build more realistic robots that can sense touch, temperature, or humidity and even distinguish between people's voices.

Feeding silkworms with either graphene or carbon nanotubes was just one of two approaches the researchers made to find a way to boost the conductivity of silk. Although some of the nanoparticles were naturally incorporated into the silk produced by the worms, this method, sadly, has not produced electrically conductive fibers.  The researchers, however, are not giving up yet as they continue experimenting using this technique.

The researchers were successful with the first approach.  Silk was treated in an inert gas environment with temperatures ranging from 1,112°F to 5,432°F (600°C to 3,000°C).  This infused the silk with carbon and graphite particles that are electrically conductive. With this technique, the scientists were able to develop strain sensors, pressure sensors and a dual-mode sensor capable of measuring temperature and pressure simultaneously.

Based on the preliminary results, Zhang is eyeing a way to create an integrated set of silk-based, self-sustaining sensors that would be powered by nano-generators.