Researchers from Johns Hopkins University (USA) developed an “electronic skin” that simulates the ability to present the skin, according to the publication IEEE Spectrum. The development proposes to use artificial prostheses, so it will be possible to return the possibility of using an artificial limb to feel pain. Why the pain? Chapter studies on the development of electronic skin Niticu Thakore, Professor of bioengineering at Johns Hopkins University are constantly asking this question.
All the matter in a practical sense. Pain receptors located in the skin, helping to protect us from getting damage. For example, from sharp knives or hot pans. In the same sense, people with an amputated limb will be able to rely on the perception of pain, which is transmitted through the artificial skin and the prosthesis that will be protected from damage last, says Thakor. Also, he offers a more integrated and to some extent even poetic explanation:
“We can restore to man the lost sense of perception: from light touch to deep pressure and pain. I think it will make the artificial dentures more ‘alive’”.
In an article published by the journal Science Robotics, Thakor, his graduate student Luke Osborn, and their colleagues describe the development and initial testing of their system “dermis” (from the English. electronic dermis, e-dermis — skin). In a recent test a team of scientists tried to add artificial prosthesis the ability to feel pain and transmit it to the bearer.
To create artificial skin researchers inspired by the functioning of biological touch receptors in our skin. The skin contains several layers of receptors. Created “dermis” also consists of many layers. However they are manufactured from piezoresistive and conductive tissues, and not to the various living cells, as in the case of real leather. In this case, the layers of artificial skin can respond to different levels of pressure: the case of strong stimulation “dermis” faster and stronger reflects the feelings, and if less intense – more slowly and weaker.
Information obtained from “electronic skin” is translated into pulses, like those used by real neurons to communicate with each other. Then by means of electrical stimulation of these neuronopathy impulses are transmitted in peripheral nerves in the skin of the amputated limb, causing a feeling of pressure and pain.
To check the system, the scientists invited a group of volunteers. Among them was 29-year-old man with an amputated above the elbow with the left hand. Within two months, Luke Osborne, was to map the peripheral nerves of an amputated limb. Through the use of weak electrical stimulation of the student was able to determine how peripheral nerves associated with phantom pains that were experienced by a visiting volunteer. In the study, Osborn found that the transfer of a certain amount of current at a certain frequency not only returned to the human sense of touch lost limbs, but also caused a phantom pain. According to Thakore, the pain was not strong, the volunteer rated it on 3 points on a 10-point scale.
The scheme of the system “dermis”
After the necessary calibration, the scientists collected the entire system: “dermis” put on the fingers of an artificial prosthesis, the model neuronopathy pulses loaded into the controller of the prosthesis, and the electric stimulator was attached to the stump of an amputated hand. Subsequent tests showed that the person is able not only to perceive the object with which he manipulates by means of an artificial prosthesis that makes him feel a phantom limb, but also to distinguish whether an object is, for example, round or sharp. In addition, the prosthesis was programmed to pain “feeling” to automatically let go of a sharp object when you define this feeling.
In this study, scientists were able to effectively convey sensory information to the nervous system using electrical stimulation of the skin amputated arm, however, the transfer of neural impulses can also be implemented using other technologies. Great expectations show implantation technology special brain electrodes, muscle reinnervation (restoration of the supply of tissue nerves that provides their connection with the Central nervous system), as well as the development of technology brain-computer interface.
“One day, all this we will be able to implant and integrate directly into our Central nervous system, and not just in the skin. But our approach is available here and now,” commented Thakur.
In the future, he and his lab plan to study other materials that could become the basis for an “electronic skin” and allow to pass a wider range of tactile sensations.
Scientists developed the technology to find their potential in robotics and augmented reality. In the details Thakor was not to go, but it is clear that tactile ability allows the robots to more effectively adapt to working with different objects and to cope with a wider range of tasks. The introduction of technology in production processes will significantly reduce the cost and expand the scope of its application.
Scientists have developed an electronic skin allows the prosthesis to feel pain
Nikolai Khizhnyak