Artificial skin made in a lab can "feel" similar to the way a fingertip senses pressure and could one day let people feel sensation in their prosthesis limbs. Researchers were able to send the touching sensation as an electric pulse to the relative "touch" brain cells in mice.
The stretchy, flexible skin is made of a man made rubber that has been manufactured to micron-scale pyramid like structures that make it extra sensitive to pressure. The researchers sprinkled this pressure sensitive rubber with microscopic cylinders of carbon that conduct electricity very well so that when the material is touched, a series of electric pulses is given off by the sensor. This series of pulses is then sent to the brain cells in a way that mirrors how touch receptors in human skin send sensation to the brain.
To test if the skin could make electric pulses that the brain could respond to, the researchers connected the synthetic skin to a blue LED light. When the skin was touched, it sent electric signals to the LED light, which pulsed in response. The sensors translated that pressure pulse into electric pulses. When the sensors in the skin sent the electric pulses to the LED- very similar to the way touch receptors in real human skin send touch sensation signals to the brain- a blue light flashed.
The researchers added a special protein that cause brain cells to react to blue light and added them to the mice brain cells. The protein let the LED act like a receptor cells in the skin. When the light flashed it sent a signal to the brain that the artificial skin had been touched. This experiment showed that, when the artificial skin was touched, the brain would respond in the same way as brains react to real skin being touched.
The next step would be to the skin in other animals and the eventual goal is to be able to stimulate the human brain and have the skin available for people.