Silk body sensors developed by Chinese scientists may help robots become more sensitive

Researchers from the Tsinghua University in China are turning to silk-based sensors to make wearable body sensors and monitoring systems more sensitive and flexible. The technology could also be used to make robots more sensitive to touch and temperature.

Silk is a natural fibre and has been regarded as one of the coveted fabrics in the world. It is stronger than steel and more flexible than nylon, according to a report by ScienceDaily.

"There is a whole world of possibilities for silk sensors at the moment. Silk is the ideal material for fabricating sensors that are worn on the body," said Dr Yingying Zhang, a researcher on the team.

The report also mentioned Dr Zhang suggesting how these sensors could one day go into making touch-sensitive robots that are a lot more realistic with them being able to "feel" temperature, humidity, and even sense difference in people's voices.

One of the uses that they team is looking at right now is remote monitoring of patients. Zhang added that silk sensors will help doctors keep track of patients through an integrated wireless system and the response time for can be a lot more rapid.

Until now, sensors placed on the human body are made with semiconductors. While they have been proven to be useful, they have other limitations. According to the report, strain sensors - which measure the change in force - cannot be reliably sensitive and stretchable at the same time.

Silk, on the other hand, can be used to sidestep this problem say the researchers. Silk also has the advantage of being bio-compatible as well as lightweight. All these qualities, according to the report, make it an ideal candidate to make sensors.

However, making sensors out of silk presents a major challenge as it is not a particularly good conductor of electricity- a quality that is necessary to make sensors work.

Zhang and her team reportedly employed two different methods to solve this. First, they claim to have treated the silk fibres in an inert environment in high temperatures ranging from 1,112 degrees to 5,432 degrees Fahrenheit. This treating caused silk to gain N-doped carbon with graphitized particles, making it electrically conductive.

The second approach involved the team feeding graphene or carbon nanotubes to silkworms hoping to have these particles incorporated with the silk. While they say that it has resulted in some of the graphene reaching the silk, they are yet to make conductive silk this way. They are reportedly still working on this technique.

Researchers presented their work at the 254<sup>th National Meeting & Exposition of the American Chemical Society.