First Pain-Sensing Electronic Skin that Reacts Like Human Skin

Imagine that you touch a hot stove, how do you perceive that the stove is hot and that you should withdraw your hand? In other words, how did you feel the pain? Doctors tell us that when the skin comes in contact with a hot object such as a hot stove, sensory receptors transfer the information to the nerve fibers at the skin, then the nerve fibers transfer it to the spinal cord and the brainstem where it is then taken to the brain and the information is registered and processed. The brain tells the skin that it has come in contact with a hot object, which then perceives the pain. All of these processes occur in microseconds, Can humans mimic this process with technology?

 

Some scientists at the RMIT University in Australia have concluded that they can mimic the pain reception process of the human skin using an electronic skin. They have built a prototype device that can replicate the way the human skin actually perceives pain and gathers information from the environment. When tested it was found that the reaction of the electronic skin was near instant, close to the instant feedback mechanism we get from our human skin. That is just wonderful.

The team at the university did not just stop there; they went further. They have built stretchable electronic devices that complement the pain reception of the prototype electronic skin which stretchable devices can also sense temperature and pressure. With this accomplishment they have integrated all these functionalities into the prototype electronic skin so that it cannot only perceive pain, it can also perceive temperature and pressure.

Lead researcher, Professor Madhu Bhaskaran, co-leader of the Functional Materials and Microsystems group at RMIT, said that this electronic skin was optimized to act as the human skin.

How the electronic skin works

This optimized electronic skin was a brain child of 3 previous devices and patents that were produced by the team. These patents were:

1. A stretchable electronic device that was transparent and unbreakable. It was made of silicon and could be worn on the skin.

2. Temperature-reactive coatings which are thinner than human hair and could react to changes in the temperature of the surroundings. The coatings were also transformable in the presence of heat.

3. A brain-mimicking electronic device that works as the brain does in using long-term memory to recall and retain previous information.

In the electronic skin prototype, the pressure sensor makes use of the stretchable electronic device and brain mimicking device, the heat sensor makes use of the temperature reactive coatings and the brain-mimicking device using memory cells, while the pain sensor combines all three technologies into one.

PhD researcher Md Ataur Rahman said the memory cells in each prototype were responsible for triggering a response when the pressure, heat or pain reached a set threshold. He hailed this as an accomplishment; the creation of the first electronic somatosensory device that will be able to replicate the complex neural mechanisms involved in transferring information from the skin to the brain and back to the skin in order to interpret what information the skin receptors were receiving from the environment. Compared to previous receptors for the skin which concentrated only on pain, he said this prototype electronic skin was the first of its kind to react to real mechanical pressure, temperature and pain at the same time and provide the correct response.

And this comes with a distinction in reception of different threshold of pain, temperature and pressure.

“It means our artificial skin knows the difference between gently touching a pin with your finger or accidentally stabbing yourself with it – a critical distinction that has never been achieved before electronically,” he said.

A purview of good things to come in the future

According to Bhaskaran: ““It’s a critical step forward in the future development of the sophisticated feedback systems that we need to deliver truly smart prosthetics and intelligent robotics.”

Yes, Imagine a prosthetic leg that could be able to feel real pain, pressure and temperature or even a robot that can distinguish different stimuli. Yes, imagine the future where human creativity has met the demands of Mother Nature. Lead researcher Professor Madhu Bhaskaran said the pain-sensing prototype was a significant advance towards next-generation biomedical technologies and intelligent robotics. We cannot wait to have people without legs know that they can have real legs right now and not feel disadvantaged. Imagine skin grafts that make you feel like this is the real thing and not an artificial skin.

The benefits of this technology are enormous. That is why I decided to include it in my solvingit? blog.

The research was supported by the Australian Research Council and undertaken at RMIT’s state-of-the-art Micro Nano Research Facility for micro/nano-fabrication and device prototyping.

‘Artificial Somatosensors: Feedback receptors for electronic skins’, in collaboration with the National Institute of Cardiovascular Diseases (Bangladesh), is published in Advanced Intelligent Systems (DOI: 10.1002/aisy.202000094).