Comment: I usually get excited when I read about how technology can improve our health unfortunately, I often get disappointed about either the slowness of bringing a device to the market or that it does not live up to the hype. However, I continue to be optimistic, this new wearable device (still in development so do not get too excited) may provide a more objective measure of stress. At the moment whether we are stressed or not is usually assessed based on circumstances and subjective descriptions of events. The device currently being tested measures cortisone levels which are at much higher levels when individuals experience chronic stress.
This article appeared in Neurosciencenews.com under the title of Signs of Burnout Can Be Detected in Sweat
When we’re in a stressful situation, whether life-threatening or mundane, cortisol is the hormone that takes over. It instructs our bodies to direct the required energy to our brain, muscles and heart. “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,” says Adrian Ionescu, head of Nanolab.
While cortisol helps our bodies respond to stressful situations, it’s actually a double-edged sword. It’s usually secreted throughout the day according to a circadian rhythm, peaking between 6am and 8am and then gradually decreasing into the afternoon and evening.
“But in people who suffer from stress-related diseases, this circadian rhythm is completely thrown off,” says 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.”
Capturing the hormone to measure it
Blood tests can be used to take snapshot measurements of patients’ cortisol levels. However, detectable amounts of cortisol can also be found in saliva, urine and sweat. Ionescu’s team at Nanolab decided to focus on sweat as the detection fluid and developed a wearable smart patch with a miniaturized sensor.
The patch contains a transistor and an electrode made from graphene which, due to its unique proprieties, offers high sensitivity and very low detection limits. The graphene is functionalized through aptamers, which are short fragments of single-stranded DNA or RNA that can bind to specific compounds.
The aptamer in the EPFL patch carries a negative charge; when it comes into contact with cortisol, it immediately captures the hormone, causing the strands to fold onto themselves and bringing the charge closer to the electrode surface. The device then detects the charge, and is consequently able to measure the cortisol concentration in the wearer’s sweat.