Fabricated Electronic Skin Perceive Pain Like Humans, Paving Way for Prosthetics and Robotics

A team from RMIT University in Melbourne, Australia has created the prototype for an electronic artificial skin that can replicate how human skin perceives pain.

The prototype device takes inspiration from the near-instantaneous feedback response human skin cells employ in receiving and processing stimuli like pain, allowing the device to react to painful sensation at almost the same speed as the real skin.

(Photo: Photo by Sean Gallup/Getty Images)
BERLIN, GERMANY - MAY 11: A stand host demonstrates a robotic prosthetic arm developed by UK startup Open Bionics mimicking his finger movements at the CUBE Tech Fair for startups on May 11, 2017, in Berlin, Germany. The CUBE Tech Fair is showcasing the projects of startups from across Europe and is running from May 10-12.

Their research, which has potentially broad applications in prosthetics, robotics, and non-invasive skin graft alternatives, is published in the journal Advanced Intelligent Systems. Furthermore, a provisional patent is already filed for the new tech, combining three previous technologies also pioneered and patented by the RMIT University team.

Replicating Human Skin, Electronically

"Skin is our body's largest sensory organ, with complex features designed to send rapid-fire warning signals when anything hurts," said lead researcher Madhu Bhaskaran. He added that their prototype is a significant advance toward intelligent robots and next-generation biomedical technologies. Also, while people receive a variety of sensations through the skin, pain response "only kicks in at a certain point," according to Bhaskaran, as is the case when people touch something sharp, or something too hot or too cold.

"No electronic technologies have been able to realistically mimic that very human feeling of pain - until now," Bhaskaran added.

In the same manner, the electronic artificial skin can instantly react upon receiving excess pressure, heat, cold, or when it reaches a threshold. As published in the journal, electronic artificial skin is achieved through three existing technologies that the RMIT University team has previously worked on.

The first is stretchable electronics that combine oxides with a silicon substrate compatible with living tissues - creating durable and wearable electronics "thin as a sticker." The second component is temperature-reactive coatings which are only a few microns thick, fabricated from a material that responds to heat stimuli. Lastly, brain-mimicking memory materials from electronic cells that can store long-term memory for the retention of previously accepted information.

A Breakthrough in Electronics

According to Md Ataur Rahman, Ph.D. researcher in the study, the memory cells trigger the response as the pressure, heat, or pain stimuli reaches its threshold. Rahman commented: "We've essentially created the first electronic somatosensory - replicating the key features of the body's complex system of neurons, neural pathways, and receptors that drive our perception of sensory stimuli."

He added that while there are existing technologies to use electrical signals to simulate pain, their work responds to actual mechanical, temperature, and pain inputs, and reacts accordingly. Rahman further added that the RMIT University prototype can distinguish touching a pin and being punctured with it, something that has not been electronically done before.

Its capability to simulate pain has applications in health where the ability of the skin to perceive pain is used as a diagnostic tool in assessing conditions such as nerve damage paralysis. An accurate receptor can replace damaged real ones, as well as augment the human's capability towards certain stimuli. In robotics, it can be used as an improvement for human-machine interfaces, serving as a feedback mechanism or as a new form of HMI.

See below video on a previous work dealing with artificial skins, created by a team from Stanford University: