In the city of Graz, flanking both sides of the river Our in Austria, it sometimes gets so cold you cannot feel your finger tips, or even your fingers anymore. Here in a lab at TU Graz, the city’s public university, on a petri dish lies a patch of ‘artificial skin’, or smart skin, its creators say is even more sensitive than the human fingertip.
(For top health news of the day, subscribe to our newsletter Health Matters)
As the world pursues ever more intently materials that will ease the alien feel of wearables, and render them more human-like, here’s a move in the right direction, as far as the future of material science goes. Last year, Anna Maria Coclite and her team of researchers from the Institute of Solid State Physics at Graz University of Technology (TU Graz) presented the results of their research to the European Research Council, to land Proof of Concept funding for their project ‘SmartCore’.
What is SmartCore? Dr. Coclite and her team had succeeded in developing a three-in-one “smart skin” hybrid material, which closely resembles human skin by simultaneously sensing pressure, moisture and temperature and converting them into electronic signals. With 2,000 individual sensors per square millimetre, the hybrid material is more sensitive than a human fingertip, giving it its reputation, and, at 0.006 millimetres thick, many times thinner than human skin. The team argued that by reacting to these three human sensory impressions, the smart skin prototype surpasses all electronic skin materials on the market to date which only react to pressure and temperature.
Dr. Coclite, a solid state physics domain expert, not only works on cutting-edge emerging tech, but also has the felicity to explain her science in a way that is easily comprehensible. In a video interview with The Hindu, she set out to decode her brainchild: “Artificial skins are a series of materials that try to emulate the functionality of our skin. Of course, you know, our human skin is very complex, it has a lot of functions, not only sensing but also thermal regulation and protection. Artificial skin projects try to emulate at least some of the functions. In our particular case, we focused on the sensing properties. So we tried to include in our device, some sensors for humidity, temperature and pressure. To show that like in human skin, you would feel as if you’re touching something colder or warmer. Similarly, this artificial skin also differentiates between colder warmer objects, objects with spikes, without spikes, and so on.”
TU Graz, Anna Maria Coclite, ERC project SmartCore | Photo Credit: © Helmut Lunghammer
Further, “Human skin has a resolution of one-millimetre square. So this means that if you have an object that is one-millimetre square or bigger, you can feel it with your finger. With the device that we have produced, we were able to even measure the electrical current from a pixel that was 0. 25-millimetre square, smaller than one-millimetre square. So, this means that you can get information also on smaller areas than human skin. How is this beneficial? First of all, it could give maybe a more integrated response with a more precise response than the human scale. And also it could be used for sensing smaller objects, for example. It has been years in the making. While work on the artificial skin project began in 2016 as funding came in, “ before that, we were working on the materials that have been used in this type of device, for example, one of the materials is a smart polymer, which changes thickness, depending on humidity and temperature.”
All about materials
Which puts everything in the hands, literally, of the materials used for the prototype, they are the fundamental constituents of the whole process. Dr. Coclite explains: “So, one is a piezoelectric material which when compressed or stretched, generates an electric current. This type of material for example, is the one that allows the artificial skin to sense force or pressure. The other material that is also very fundamental in this is the smart polymer that changes thickness depending on humidity and temperature, and in particular, these two materials have been combined in various nano rods. So very, very, very small rods in which the polymer is in the middle and the piezoelectric material is on the outside. And what happens is that when the polymer expands, because the temperature or humidity changes, it applies a pressure on the piezoelectric material, and then consequently, an electrical current.”
Naturally enough, the inspiration comes from the original - the human skin- but also other biomimetic examples, for instance, pine cones, or the leaves of plants, they also show this kind of change in shape and thickness depending on humidity and temperature. So, the smart polymer, in some ways, emulates other such phenomena in nature. Are these materials bio-compatible? “We wanted the materials to be biocompatible, because we had considered applications in the biomedical segment, for use among humans. To create these sensors and especially to have them so tiny, so that the resolution can be below the resolution the human skin is capable of, we use the precise chemical vapor deposition technique to have a fine product.”
Being sustainable
For those also conscious of leaving a waste trail, and making sure any project is sustainable, the other advantage Dr. Coclite’s team provides is the sizing. “All the sensors that we use are all made of thin films much smaller than one millimeter. This means that the quantity of material used is really small. And therefore there is not too much of footprint that is left from these materials. The thickest part of this whole device is actually the substrate where we have used plastic foil, but it could also be paper foil, with better biodegradability. So, one could make them also with much more eco friendly materials than our first prototype,” Dr. Coclite explains.
Real life bio uses
With the success of the prototype and armed with ERC funding smoothing out the path ahead, Dr. Coclite and her team hope to further examine the implications of smart skin for health care, and robotics. One area of practical application that really excites her and the team is prosthetics. “The artificial skin could cover the prosthetics and help the patient with the amputation regain sensation. So I wouldn’t say that it would have a therapeutic effect, but it could be used for some medical device, for example, to give back the sensation to people that have lost a limb.” Such intelligent prosthesis could be a possibility if researchers are able to integrate the signals from the smart skin with human neural networks, teaching the brain to read these new signals. A lot of work is happening on this front of research now.”
According to the World Health Organisation (WHO), around 200,000 people are severely burned every year and suffer a complete loss of sensation due to the death of the skin receptors. Smart skin could act as a “plaster” to help burn victims regain their sensations. For Dr. Coclite, this might probably the best she could hope for. “I think the biomedical application development is the one area I am more interested in. Because I think it would be really cool, from my point of view, if one of my research projects could help give back the sensation to patients who have lost it or solve real problems.”
Among the projections, the smart skin could also be used as a sensor with smart watches, when it is programmed to collect precise information about the health status of patients. In this way, skin moisture, pH value and temperature could be continuously monitored.
A wireless job
Armed with the PoC funding, the scientist wants to develop the wireless connection of the electronic skin to a real-time monitoring system. This is to transmit important data on temperature, humidity and pressure via Bluetooth to a smartphone app that can be used to display the recorded sensory impressions. As Dr. Coclite says, the central point in taking the prototype from the lab to the field, would be to achieve some kind of wireless detection; the current prototype needs to be connected with wires. It is her hope that this amplification is likely to come through over a timeline of the next five years. She also points to inspiring work done by a team at Stanford, producing soft integrated circuits that convert sensed pressure or temperature to electrical signals similar to nerve impulses used to communicate with the brain. “Even though they use different approaches, and different materials, it is absolutely inspiring work to show how artificial skin can communicate with the brain. That gives us hope,” she says.
Outlining the tasks up ahead for her team, she says it would be in optimising the prototype, develop wireless detection, and working with companies that would be interested in testing this application in real time, in real situations. “At the same time, we will keep working on this type of responsive materials and biomimetic materials.”
“I really think there is a lot going on there. What would also be good is to combine all these sensors, or wearables, with learning artificial intelligence with learning algorithms. So that really, I think, in a future that is not so far away, we will be, you know, completely hooked up with sensors that will check all our vitals constantly. This is not too far in the future,” she says.
Realistic timeline
Also, with the unexpected fillip that scientific research received after the COVID pandemic, she feels funding for research is critical. “It is now obvious that putting money into research can really benefit the larger society, if you look at the development of COVID vaccines and how quickly we got them. It is clear that if you fund innovation, then the whole world benefits from it,” she says.
Dr. Coclite’s timeline is built on optimism for the future, but also her cognition of what is happening in the wearables segment, which is practically an explosion in terms of research happening in the field and multiple inter-sectoral collaborations fuelled by funding. Given how far she and her team have travelled in a relatively short time for science - the last six years or so - it is easy to share her optimism, coming as it does from one who’s proved she’s certainly got the touch.
Published - January 25, 2024 09:48 pm IST
