Flexible Sensor Could Make Artificial Skin More Sensitive to Touch, Humidity

Researchers have found a way to make a flexible sensor that can be embedded in artificial skin or e-skin. The sensor is made using gold particles and a certain kind of resin. Scientists say that people with the new prosthetics could feel changes in the environment via the e-skin.

The artificial skin, developed by researchers at the Technion-Israel Institute of Technology, can detect touch, humidity and temperature - just like real human skin.

The new skin is "at least 10 times more sensitive in touch than the currently existing touch-based e-skin systems," says Professor Hossam Haick, team leader of the research.

There are many hurdles in making artificial skin that can function as real skin; the sensor in the skin must be able to run on low voltage, be sensitive to pressure, make multiple measurements at the same time such as checking temperature, humidity or chemical presence. Also, sensors that can be cheaply built can achieve commercial success.

The new sensor has all these qualities, researchers say.

The new sensor is made of monolayer-capped nanoparticles, which are about 5-8 nanometers in diameter. These nanoparticles are made of gold and are surrounded by ligands or connector molecules. Haick describes the entire construction as being similar to a flower.

The "monolayer-capped nanoparticles can be thought of as flowers, where the center of the flower is the gold or metal nanoparticle and the petals are the monolayer of organic ligands that generally protect it," says Haick in a news release.

The sensor, when laid on a substrate such as PET (flexible polyethylene terephthalate), conducted electricity depending on the how the material was bent. The sensor can detect pressures varying from tens of milligrams to tens of grams.

Since, the sensor is sensitive to changes in pressures; it could be even used in detecting cracks on bridges.

There have been many breakthroughs in the field of artificial skin development. A team of experts had recently discovered a way to make stretchable circuits using foam substrates, which could help create artificial skin that could feel touch, pain and tickles.

Also, researchers at the Georgia Tech had constructed "smart skin" using nano-sized 3D array. This sensor comprised of around 8,000 transistors that were embedded on crystals of zinc oxide. Self-healing polymers were also used in developing artificial skin as the substance could recover its mechanical properties and regain its original form after being broken several times.