Wednesday, July 10, 2013: The day is not far when amputees would be able to feel changes in their environment through prosthetic limbs. Researchers at the Technion-Israel Institute of Technology have reportedly made a breakthrough using tiny gold particles and a special resin to develop a new type of flexible sensor. The sensor could be integrated into the artificial skin allowing it to detect touch, humidity and temperature as well. The research team said that the flexible sensor can be built at a low cost.
According to lead researcher Hossam Haick, the e-skin was “at least 10 times more sensitive in touch” than any other existing touch-based e-skin systems.
It is pertinent to note here that it’s the first artificial skin sensor to record temperature and humidity. Nevertheless, the researchers say that “it can sense them quite accurately, reporting back with only a small margin of error for each. The technology is based on gold nanoparticles that are mounted to metal and a flexible plastic,” The Verge said in a report.
In their research, the Technion team used monolayer-capped nanoparticles that are only 5-8 nanometers in diameter. They are made of gold and surrounded by connector molecules called ligands. In fact, “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.
The team discovered that when these nanoparticles are laid on top of a substrate – in this case, made of PET (flexible polyethylene terephthalate), the same plastic found in soda bottles – the resulting compound conducted electricity differently depending on how the substrate was bent. (The bending motion brings some particles closer to others, increasing how quickly electrons can pass between them.) This electrical property means that the sensor can detect a large range of pressures, from tens of milligrams to tens of grams. “The sensor is very stable and can be attached to any surface shape while keeping the function stable,” says Dr Nir Peled, Head of the Thoracic Cancer Research and Detection Center at Israel’s Sheba Medical Center, who was not involved in the research.
And by varying how thick the substrate is, as well as what it is made of, scientists can modify how sensitive the sensor is. Because these sensors can be customised, they could in the future perform a variety of other tasks, including monitoring strain on bridges and detecting cracks in engines.
“Indeed,” says Dr Peled, “the development of the artificial skin as biosensor by Professor Haick and his team is another breakthrough that puts nanotechnology at the front of the diagnostic era.”
