A small, wearable sensor that can detect levels of the stress hormone cortisol in sweat may soon help warn when people are nearing burnout, a study reported.
Engineers at the Swiss Federal Institute of Technology Lausanne (EPFL) and start-up Xsensio said that the tool could help to objectively quantify stress levels.
The device is placed directly onto the wearer’s skin and offers both high sensitivity and very low detection limits, the researchers said.
Alongside burnout, such wearables could also be used to help study other stress related conditions, like obesity.
A small, wearable sensor that can detect levels of the stress hormone cortisol in sweat may soon help warn when people are nearing burnout, as pictured, a study reported
Manufactured by our adrenal glands from cholesterol, cortisol is a steroid hormone that performs various essential functions in the human body, including in regulating blood pressure, blood sugar levels and metabolism.
The hormone can also affect both immune system and cardiovascular functions — and when we are placed in stressful situations, cortisol works to ensure the body directs energy to the brain, heart and muscles to handle the situation.
‘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 paper author and EPFL nanoelectronics expert Adrian Ionescu.
Normally, cortisol is secreted in accordance with the body’s daily rhythms — with its release peaking between 6am and 8am, with levels then decreasing into the afternoon and evening.
‘But in people who suffer from stress-related diseases, this circadian rhythm is completely thrown off,’ explained Professor Ionescu.
‘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.’
While cortisol levels can be measured from blood samples, they can also be determined by analysing one’s sweat, saliva and urine.
Manufactured by our adrenal glands from cholesterol, cortisol is a steroid hormone that performs various essential functions in the human body, including in regulating blood pressure, blood sugar levels and metabolism. Pictured, a molecular model of cortisol
In their study, Professor Ionescu and colleagues developed a wearable smart patch which contains a transistor and a graphene electrode to which are attached special molecules which bind with cortisol and have a negative charge.
When these molecules capture a cortisol molecule, they fold onto themselves, bringing the negative charge close to the electrode’s surface where it can be detected — thus registering the presence of the cortisol in the sweat.
It will be the first device to be able to provide round-the-clock cortisol monitoring, the researchers have said.
‘That’s the key advantage and innovative feature of our device. Because it can be worn, scientists can collect quantitative, objective data on certain stress-related diseases,’ Professor Ionescu added.
‘And they can do so in a non-invasive, precise and instantaneous manner over the full range of cortisol concentrations in human sweat.’
Professor Ionescu and colleagues developed a wearable smart patch which contains a transistor and a graphene electrode to which are attached special molecules which bind with cortisol and have a negative charge, as pictured. When these molecules capture a cortisol molecule, they fold onto themselves, bringing the negative charge close to the electrode’s surface where it can be detected — thus registering the presence of the cortisol in the sweat
The researchers have evaluated the effectiveness of the sensor on Xsensio’s proprietary ‘Lab-on-Skin™’ platform — and now looking to put it through its paces on real-life patients.
‘We look forward to testing this new sensor in a hospital setting and unlocking new insight into how our body works,’ said Xsensio CEO Esmeralda Megally.
The researchers have teamed up with experts from the Lausanne University Hospital to try out the cortisol monitoring patches on both healthy subjects and individuals suffering from Cushing’s syndrome, Addison’s disease and stress-related obesity.
The body produces too much cortisol in the case of Cushing’s syndrome and, with Addison’s disease, not enough.
Alongside providing 24-hour cortisol level monitoring, the patch could also help doctors to evaluate problem stress levels in patients with psychological diseases.
‘For now, they are assessed based only on patients’ perceptions and states of mind, which are often subjective,’ said Professor Ionescu.
‘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.’
In the future, the researchers added, the sweat sensor design could be integrated into smart bracelets and similar fitness trackers.
‘The next phase will focus on product development to turn this exciting invention into a key part of our Lab-on-Skin sensing platform, and bring stress monitoring to next-generation wearables,’ said Ms Megally.
The full findings of the study were published in the journal Communications Materials.
