Researchers at the University of Pittsburgh in collaboration with engineers at MIT have demonstrated that a substance known as BZ gel can sense and respond to stimuli, similar to human skin.
When placed in an environment with certain agents, the gel, with a chemically-attached catalyst, will begin to pulse as it expands and contracts. Few materials can mimic this autonomous oscillation. The gel can, with the potential to restart pulses by sensing touch.
Anna Balazs, a distinguished professor of chemical and petroleum engineering at Pitt, said the gel begins oscillating again as it senses touch, making it very similar to a human.
"When you touch your skin, then it sends out a chemical signal throughout your body indicating that you've been touched," Balazs said. "Well [it's] the same thing with this purely synthetic gel. When I touch the gel with a certain threshold of pressure, it sends out a signal that it's been touched and it starts to oscillate again."
The gel is challenging to create according to Balazs. It was first synthesized in the 1990s. The recent research was to prove a theory that oscillation can be triggered by putting pressure on the gel and was performed with the help of Krystan Van Vliet and Paul M. Cook of MIT and Irene Chen who made the material for the experiments.
Balazs said the current practical uses of such a substance are limited, but the knowledge of the material will allow researchers to look into uses in the medical and robotics fields.
"The reagents that you put this gel into to make it work are very acidic, so right now it's not optimal," Balazs said. "But eventually you could imagine that you could have a drug release device where, if you pressed on it, then you would have the release of the drug."
Balazs said the gel resembles a beating heart when oscillating autonomously. She said the stimulus response characteristic provides the possibility of artificial skin with sensory capabilities.
"What you need is a skin that mimics the biological skin that actually feels pressure," Balazs said. "So now here's a new material that feels pressure and reacts to pressure by sending a chemical signal."