A plastic "skin" able to feel pressure has be created at stanford by the work of Zhenan Bao, a professor of chemical engineering. The new material is able to know how hard it is being pressed by carrying an electrical impulse to a living brain cell.
Bao has spent years in trying to develop a material that will cover a prosthetic limb that will have the same abilities as our skin; signals that can send pressure, temperature and pain signals to the brain.
Bao's work, reported today in Science, takes another step toward her goal by replicating one aspect of touch, the sensory mechanism that enables us to distinguish the pressure difference between a limp handshake and a firm grip.
"This is the first time a flexible, skin-like material has been able to detect pressure and also transmit a signal to a component of the nervous system," said Bao.
Bao was responsible for leading a 7 person team to take this initial step forward in trying to replicate the skins abilities.
So how does it work?
The idea is initially that the finalized skin like material is made up of two layers:
The top layer is a sensing mechanism which is able to detect the pressure (the range of pressure is amazing starting from as little as a touching finger). Bao a few years back had been able to with her team, use plastics and rubbers as sensors of pressure by looking at how the molecular structures of the materials will spring back. This would begin a a thinking process for the team as they were able to increase the natural pressure sensitivity by producing a weave like pattern into the thin plastic.
Once the pressure sensitivity was achieved hey now had to capture the signal; this was done by billions of scattered carbon nano-tubes through the weaved material, when pressure is applied to the material these make contact and electrical conductivity is produced. The more the pressure the more closer the nano-tube are squashed together therefore increasing the electricity flowing through the sensor. The electrical impulses are very similar to that of Morse code and these varied impulses are sent as short pulses via the sensing mechanism to the second layer of the material, a delicate electronic circuit.
The second layer is an electronic circuit which can transport electrical signals and turn them into biochemicals so they will be compatible with the nerve cells in the human body. What is amazing about this circuit is that it has been designed to bend without breaking. Now the team has the sensor and the circuit board, Bao's team had to prove that the signal could work with a biological neuron. With the help of Karl Deisseroth a fellow professor at stanford is an expert at bio-engineering. They were able to produce a line of neurons replicating the bodies natural nervous system.The heavy electrical signal changed to very tiny impulses this was able to activate the neurons, which can then send the signals to the brain.
Bao and her team has massive ambitions for there research they will continue to look at getting the material to distinguish between hot and cold water, touching different materials and maybe even the sense of being lightly touched.
Bao stated, "We have a lot of work to take this from experimental to practical applications," Bao said. "But after spending many years in this work, I now see a clear path where we can take our artificial skin."
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