The future in your palm - a non-contact wearable that studies skin flux to estimate health

The Hindu

02-05-2025

William Blake could have scarcely estimated just the expanse that a palm full can contain, when he said 'hold infinity in the palm of your hand', but science today can give him a fair estimate. Smaller and smaller wearable devices, with the surface area the extent of a mere watch dial, have come to play, measuring all kinds of health parameters on the go – heart rate, blood oxygen, even continuous blood glucose levels. Here's yet another wearable, but one with a difference. Researchers have zeroed in on a wearable that can study the streams of molecular substances that pass through the skin, as a measure of studying the health status of individuals. What is different is that this wearable is 'non contact' relying on an enclosed chamber immediately adjacent to the skin's surface to do its job.
A collaboration of American and South Korean experts from the domains of materials sciences, dermatology, engineering, bio-medics and chemistry worked to produce a small device, just about the size of a smartphone face, that has demonstrated unique capabilities to measure the flux of water vapour, volatile organic compounds and carbon dioxide at various locations on the body, to examine not just skin health but general health too. The particular use has been to study wound healing properties in diabetes and has the additional advantage of non contact operation, therefore potential damage to fragile tissues can be avoided.
Catch it early, cost-effectively
John A. Rogers who is the Lewis Simpson and Kimberly Querry Professor of Material Sciences and Engineering, Biomedical Engineering, and Neurological Surgery at the Northwestern University, U.S. and is steering the research says his team has been working on wearable technologies for about two decades now. 'With the COVID pandemic, there began a heightened awareness of the value of technologies that could continuously monitor health status; catch very early signs of disease or infection or health complications, in remote and, cost-effective ways. We have introduced a number of skin interface devices for measuring vital signs like electrocardiograms, blood oxygenation, body temperature.'
The wearable in question however is unique, he explains. 'It is unique in the sense that the sensors don't contact the skin. They're actually separated from the skin, and instead of directly measuring underlying physiological processes- cardiac cycles, lung function, for example, we're measuring, properties of the skin itself and measuring species that emerge from the body through the skin to the surrounding environment. And likewise, we are also measuring chemical species that can move from the environment into the body through the skin.'
He adds this is something that people haven't looked at before, and experiments have proved that there's a lot of interesting information that emerges, related to wound healing but also basic health. The authors write up the results in a recent paper published in Nature journal. This technology can provide unique insights for clinical decision-makers managing conditions such as dermatological diseases and dermal wounds, but who are also interested in understanding the underlying pathophysiologies better. It can also monitor hazardous chemicals that enter the human body via the skin, making it a viable option to monitor the health of persons working in hazardous industries and zones.
How the skin works
He continues to explain: The skin is a layered substance with a pretty good impermeable water barrier on the very surface - called the stratum corneum. Underneath that is the epidermis and then the dermis. Those tissues are fairly permeable to water. But the stratum corneum is a very thin layer of dead cells, and serves as a barrier. If that barrier did not exist, you'd have tons of water evaporating and water loss just coming out through all surfaces of the body. So, it performs a very critical function as a water barrier. If that's compromised in any way, then, you can be at risk for dehydration and, degradation in the properties of the healthy living part of the skin, the epidermis and, and the dermis.
Therefore, measuring water permeation through the skin can tell you a lot about the barrier function of the skin, and various skin disorders can reduce the barrier functions, Prof Rogers explains. 'You can monitor that. Transcutaneous CO₂ for example, coming right through the surface of the skin is important, and physicians already know how to interpret that.' He adds that their assumption is that the device, with its capacity to read and measure the environmental species that enters the body through the skin will likely yield additional insights that physicians are not aware of yet.
What the device does
The device itself, he describes, is like a small pocket, with wireless electronics that can transmit data to your phone. It also has a chamber that forms a microclimate when the device is sealed against the surface of the skin. Suspended within that chamber is a suite of sensors, very small semiconductor devices that can measure water, CO₂, and various volatile organic compounds. On the back, there is a valve that can be opened and closed through a wireless trigger. When the valve is closed and the device is on the surface of the skin, the sensors measure a gradual increase in the concentration of water vapor and CO₂. When the valve is open to the surrounding environment, the heightened concentrations of those species can dissipate because now those species can just diffuse out to the surrounding environment. We make measurements with the valve closed, then open, and so on. The rate at which those concentrations increase determines the flux.'
These low-cost devices can just be adhered to the surface of the skin, and measure these properties continuously, without a physician having to be at call. The device can be mounted anywhere on body and track outward flux and also inward flux at the same time.
An additional vital sign
Prof. Rogers says there has already been some interest in the device from the perfumery industry. And while it has not yet been studied in an environment where the patient has suffered burns, he added that it would be an exciting pathway to launch on. Once adequate data emerges from the device over a period of time, measurements off the skin might turn out to be an additional vital sign that doctors rely on to estimate the health of their patients, in addition to the conventional vital signs.