Wearable patch uses sweat to detect stress levels

A device can help identify stress, burnout and diseases like Cushing's and Addison's.

Dave Yasvinski 3 minute read February 8, 2021
stress test

The problem with cortisol, a stress hormone, is it is extremely difficult to monitor current levels in a patient’s system. Getty

A small, wearable device may soon help people prone to sweating the small stuff keep tabs on their stress levels and even extinguish burnout before it begins.

The technology, developed in EPFL’s Nanoelectronic Devices Laboratory (Nanolab) in Lausanne, Switzerland, is capable of continually measuring the concentration of cortisol in a patient’s sweat once placed directly on their skin. Cortisol, the body’s main stress biomarker, is responsible for a host of vital tasks, including regulating metabolism, blood pressure and blood sugar levels. It also has a role in immune and cardiovascular functions. The hormone, which is typically released throughout the day, is guided by the body’s circadian rhythm to peak at around 7 am and then taper off throughout the afternoon and evening.

Whenever a person finds themselves in a stressful situation, cortisol takes the wheel, diverting energy to vital systems in the brain, heart and muscles — sometimes to the detriment of the host. “Cortisol can be secreted on impulse — you feel fine and suddenly something happens that puts you under stress, and your body starts producing more of the hormone,” said Adrian Ionescu, the head of Nanolab.

“But in people who suffer from stress-related diseases, this circadian rhythm is completely thrown off. And if the body makes too much or not enough cortisol, that can seriously damage an individual’s health, potentially leading to obesity, cardiovascular disease, depression or burnout.”

The problem with cortisol is it is extremely difficult to monitor current levels in a patient’s system. A blood test only provides a snapshot of concentration at a given moment but the hormone also shows up in saliva, urine and — of particular interest to Ionescu’s team — sweat. They quickly got to work on equipping a wearable smart patch with a tiny sensor in an attempt to keep up with the rise and fall of cortisol.

The device they designed contains a transistor and electrode made from graphene, a substance that offers high sensitivity and low detection limits and is capable of continuously monitoring cortisol levels. The patch employs negatively charged fragments of single-stranded DNA or RNA, which can bind to specific compounds — such as cortisol — and capture and measure the concentration of the hormone.

It is now the first system to effectively track levels of the hormone across the circadian cycle. “That’s the key advantage and innovative feature of our device,” Ionescu said. “Because it can be worn, scientists can collect quantitative, objective data on certain stress-related diseases. And they can do so in a non-invasive, precise and instantaneous manner over the full range of cortisol concentrations in human sweat.”

The device, which will now be tested in a hospital setting in Switzerland, may hold the key to more effectively treating people with Cushing’s syndrome (the body generates to much cortisol), Addison’s disease (not enough cortisol) and perhaps even shed light on stress-induced psychological diseases. “For now, they are assessed based only on patients’ perceptions and states of mind, which are often subjective,” Ionescu said. “So, having a reliable, wearable system can help doctors objectively quantify whether a patient is suffering from depression or burnout, for example, and whether their treatment is effective. What’s more, doctors would have that information in real time.

“That would mark a major step forward in the understanding of these diseases.”


Dave Yasvinski is a writer withHealthing.ca



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