© 2021 EPFL

Stress is one of the biggest health risks people have to contend with. But it is not always so obvious when someone is suffering from it and what form that stress takes. Up until now, it has not been possible to measure stress levels in an objective way. Therefore, the invention of a sensor chip that can measure concentrations of the stress hormone cortisol in human sweat can justifiably be hailed as a major breakthrough.

Doctors will in future be able to better understand and treat stress-related conditions, such as burnout and obesity, through near-continuous monitoring.

The small portable sensor was developed by engineers at the Nanoelectronic Devices Laboratory (Nanolab) of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland. The device can be attached directly onto a patient’s skin. Doctors will in future be able to better understand and treat stress-related conditions, such as burnout and obesity, through near-continuous monitoring.

Measuring cortisol

The device incorporates a transistor and an electrode made of graphene, which offers a high range of sensitivity due to its unique properties. The graphene is functionalized by aptamers. These are short fragments of single-stranded DNA or RNA that have the ability to bind to specific compounds. The aptamer in EPFL’s device has a negative charge. When it comes into contact with cortisol, it immediately captures the hormone, causing the strands to fold on top of each other. This then moves the charge closer to the electrode surface. The device then detects the charge and can thereby measure the cortisol concentration that is present in sweat.

Stress meter

Cortisol is a corticosteroid hormone that is made in the adrenal cortex from cholesterol. Its secretion is regulated by the adrenocorticotropic hormone (ACTH), which is produced by the adeneohypophysis.

Cortisol performs essential functions in the human body, such as regulating metabolism, blood sugar and blood pressure. It also affects the immune system and cardiovascular functions.

When a person finds themselves in a stressful situation, cortisol is the hormone that takes over. It instructs the body to send needed energy to the brain, muscles and heart. When the body makes too much or not enough cortisol, it can seriously damage an individual’s health. This in turn potentially leads to obesity, cardiovascular disease, depression or burnout.

Read about another invention that measures heart rate variability here.

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About the author

Author profile picture Ewout Kieckens is a Dutch journalist in Rome who writes about Italian lifestyle and culture. He has written books on diverse subjects such as the Vatican and Italian design. He is very interested in innovations, especially Italian contribution to progress.