THE POWER OF TOUCH

We all know that skin is the largest organ in the entire human body. It has many lifesaving functions such as keeping bacteria from entering the body, protecting the body from losing vital fluids, regulating the body’s temperature. Generally to treat severe burns, surgeons remove all the dead skin and replace it using skin grafts from the person’s body. But treating people who have severe burns of 80% or more of their body is difficult, as there isn’t any extra skin to use. That’s when doctors use artificial skin or synthetic skin grafts to keep the severe injury covered while the body has time to stabilize.

Artificial skin created in lab can “feel” similar to fingertip sense pressure, and researchers say that one day it could let people feel sensation in their prosthetic limbs. The stretchy, flexible skin is made of a synthetic rubber designed to have micron-scale pyramid like structure that makes it sensitive to pressure and this rubber is sprinkled with carbon nanotubes so that a series of pulse is generated form the sensor when the material is touched. This is then sent to brain in a way that resembles the touch receptors in human skin.

To test whether the skin could create electric pulses that the brain cells could respond to, the synthetic skin was connected to a blue LED circuit. When the skin war ouches the sensor sent electric pulses to the LED the sensor translated that pressure pulse into an electric pulse by which a blue light is flashed. The higher the pressure, the faster the LED is flashed.

The researchers were able to send the touching sensation as an electric pulse to the relevant “touch” brain in mice. They added channelrhodopsin to the mouse brain cell; it is a special protein that causes brain to react to blue light. And this channelrhodopsin lets the LED light to act as receptor cells in the skin i.e., when the light is flashed it sends a signal to the brain that the artificial skin is touched. The experiment showed that, when the artificial skin was touched, the brain cells would react in the same way as brains react to real skin being touched.

Using light to stimulate brain cells is a fairly recent area of study called optogenetics, in which scientists add special proteins to brain cells that let them react to light and shows scientists how different parts of the brain work. The advantage of using optogenetics over other technologies that directly stimulate neurons, such as electrodes directly attached to brain tissue, at higher frequencies can be used. Having a technology that can stimulate the cells at higher frequencies is important because it more accurately recreates the way that receptor cells send signals to our brains.

The testing is still in the early phases, and the skin hasn’t been tested with human neurons. They had connected the sensors to a robotic hand and were able to record the pulses. However, it was just to prove that the technology was able to send a signal that could be registered by same technologies used in advanced prosthetic technologies.

By, T.G.Lisa Sunil(B.E-3/4)

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