Technology can be awkward. Our pockets are weighed down by giant smartphones that can't be pulled out quickly when you're running somewhere. Attempts to make our devices more accessible using smartwatches are so far hardly successful. But what if a part of your body became a computer, with a screen on your hand and maybe even a direct link to your brain?
Artificial electronic skin (e-skin) may one day make this a reality. Scientists are developing flexible, bendable and even stretchable electronic circuits that can be applied directly to the skin. And besides turning your skin into a touchscreen, this approach can be useful if a person has been burned or has problems with the nervous system.
The simplest version of this technology is electronic tattooing. In 2004, scientists from the United States and Japan presented a pressure sensor circuit made from pre-stretched thin silicon strips that could be applied directly to the forearm. But inorganic materials like silicon are tough, and leather is flexible and stretchable. Therefore, researchers are looking for electronic microcircuits that can be made from organic materials (usually special plastics or forms of carbon like graphene that conduct electricity) as the basis for electronic skin.
A typical electronic skin consists of a matrix of various electronic components - flexible transistors, OLEDs, sensors, and organic photovoltaic (solar) cells - connected to each other using stretch or flexible conductive wires. These devices are made from very thin layers of material that are sprayed or vaporized on a flexible basis, producing large (up to several tens of square centimeters) electronic circuits in a skin-like shape.
Much of the effort to create this technology in the past few years has been driven by robotics and the desire to give machines a human tactile quality. We have e-skin devices that sense the approach of objects, measure temperature, and apply pressure. This helps robots to be more aware of their surroundings (and people who may be in the way). When integrated into wearable technology, e-skin can do the same for humans, for example by detecting harmful or unsafe movements during exercise.
This technology has also led to flexible screens; at least one company hopes to turn skin into a touchscreen, using sensors and pico projectors instead of a display.
But can we one day build this technology right into our bodies? Will this be common? The problem with organic electronics at the moment is that it is not very promising and does not show the highest performance. After all, even e-skin wrinkles form. The layers disintegrate and the schemes are broken. In addition, atoms in organic materials are more chaotically arranged than in inorganic materials. Because of this, electrons in them move 1000 times slower, devices work slower and have problems with heat removal.
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Biocompatibility
Another major challenge is how to integrate e-skin into the human body so as not to create associated medical problems and tie it to the nervous system. Organic materials are carbon-based (just like our bodies), so in a sense, they are biocompatible and not repelled by the body. But carbon particles pass well through the cells that make up our body, which means they can lead to inflammation, trigger an immune response, and possibly even lead to the appearance of tumors.
Yet scientists have had some success trying to tie electronic devices to the nervous system. Scientists at Osaka University are developing brain implants from a flexible matrix of organic thin-film transistors that can be activated by mere thought. The challenge is that an invasive approach can lead to problems, especially when we start testing the technology in humans.
In the coming years, we will definitely see prototype e-skin devices gain traction in the form of wearable bodily sensors and possibly devices for extracting energy from body movements. Much more time will be spent on the development of complex microcircuits, such as those present in our smartphones. How many people will go for it? Are you ready to become a cyborg 99%?
ILYA KHEL