Researchers have developed electronic artificial skin that responds to pain just like real skin. This discovery, published in the journal Advanced Intelligent Systems, paves the way for better prosthetics, smarter robotics, and non-invasive alternatives to skin grafts.

A prototype device, developed by a team at RMIT University in Melbourne, Australia, can electronically replicate how human skin feels pain. The device mimics the body’s near-instantaneous feedback and can respond to painful sensations at the same speed of light as nerve signals to the brain.

Lead researcher Professor Madhu Bhaskaran said the pain sensor prototype was a significant step forward in biomedical technology and next-generation intelligent robotics.

The skin is the largest sensory organ in our body with complex functions designed to send quick alert signals when something hurts. We feel things through our skin all the time, but our response to pain only occurs at a certain point, such as when we touch something too hot or too sharp. No electronic technology has been able to realistically simulate this very human feeling of pain – until now. Our artificial skin reacts instantly when pressure, heat or cold reaches a painful threshold. This is an important step forward in the future development of the sophisticated feedback systems we need to create truly intelligent prostheses and intelligent robotics.

Lead Investigator Professor Madhu Bhaskaran

Functional sensor prototypes

In addition to the prototype pain sensor, the research team has also developed devices with stretchable electronics that can sense and respond to changes in temperature and pressure.

Bhaskaran, co-leader of the functional materials and microsystems group at RMIT, said three functional prototypes were developed to electronically transfer key functions of skin sensitivity. With further development, extensible artificial skin may also be a future option for non-invasive skin grafts where the traditional approach is not viable or does not work.

“We need further development to integrate this technology into biomedical applications, but the basics – biocompatibility, skin-like extensibility – are already there,” the scientist said.

How to make e-skin?

The new study, filed as a provisional patent, combines three technologies previously developed and patented by the team:

Resilient Electronics: Combining oxide materials with biocompatible silicone to create sticker-thick, transparent, shatter-proof, and wearable electronics.

Temperature-reactive coatings: Self-modifying coatings 1000 times thinner than human hair, based on a material that transforms when exposed to heat.

Brain Mimic Memory: Electronic memory cells that mimic the way the brain uses long-term memory to recall and store previous information.

The prototype pressure sensor combines stretchable electronics and long-term memory cells, the heat sensor combines thermosetting coatings and memory, and the pain sensor combines all three technologies.

Ataur Rahman, Ph.D., said that memory cells in each prototype are responsible for triggering a response when pressure, heat, or pain reaches a set threshold.

In fact, we created the first electronic somatosensors that reproduce key features of the body’s complex system of neurons, neural pathways, and receptors that govern our perception of sensory stimuli. While some existing technologies have used electrical signals to simulate different levels of pain, these new devices can respond to real mechanical pressure, temperature and pain and provide the correct electronic response. This means that our artificial leather knows the difference between lightly touching a pin with a finger or accidentally pricking it – an important distinction that has never been achieved electronically before.

Ph.D. Ataur Rahman

The study was supported by the Australian Research Council at RMIT’s state-of-the-art micronano-nanotechnology research center for micro / nanotechnology and device prototyping.