Cortisol measuring patch
Researchers at Stanford University, working under the guidance of associate Professor Alberto Salleo, have developed a patch that absorbs sweat and determines the concentration of cortisol contained in it, also known as stress hormone.
The concentration of cortisol, which is not only responsible for the emotional state, but also involved in many important physiological functions, including blood pressure regulation, metabolism and immune responses, naturally increases and decreases throughout the day, and stressful effects can cause strong sharp jumps in the level of this hormone. The concentration of cortisol in the body is an objective indicator of the strength of emotional or physical stress, which doctors can use to assess the functional state of the pituitary gland and adrenal glands.
However, modern laboratory methods of measuring it require several days to obtain a result. By this time, the hormone level in the body changes greatly and the selection of the treatment method loses its effectiveness. A fast, portable method for assessing cortisol levels would allow patients with appropriate disorders to monitor their condition at home. In addition, it could be used to assess the emotional state of young children, including those who cannot talk and are unable to report the stress they are experiencing.
The authors propose to use an elastic biosensor developed by them to solve this problem, which is a patch attached directly to the surface of the skin. This patch is soaked with sweat secreted by the skin and analyzes its composition, allowing you to almost instantly assess the level of cortisol in the body.
The difficulty of creating a cortisol biosensor was the lack of charge in its molecules, since earlier versions of such biosensors were designed to register positively or negatively charged molecules. To overcome this problem, the developers have created an elastic rectangular sensor, inside which there is a membrane selectively binding cortisol molecules. After attaching the skin, it absorbs sweat that passively penetrates through the pores in the lower layer of the patch. Sweat accumulates in a reservoir, on top of which there is a cortisol-sensitive membrane. The charged ions contained in sweat, including potassium and sodium ions, pass through the pores if they are not blocked by cortisol molecules. The sensor evaluates the amount not of cortisol itself, but of such delayed ions. The top waterproof layer protects the entire system from contamination.
In order to measure the level of cortisol, a person only needs to sweat, attach a patch and connect it to an analyzer that gives results within a few seconds.
Both in laboratory conditions and when tested "in the field" – attached to the arm during 20-minute runs – the biosensor produced results completely comparable to the results of traditional laboratory tests.
Over time, the developers plan to create a fully integrated device based on this sensor. In addition, they hope to make it more reliable and accurate, as well as reusable. In the future, the developed approach can be used to create a sensor that determines the concentration of cortisol in saliva, which will save patients from having to sweat. Another area of further work is to modify the approach for registering other biomarkers and, ultimately, simultaneously measuring the levels of several molecules, which will allow obtaining a clear picture of what is happening in the body.
Article by Onur Parlak et al. The molecularly selective nanoporous membrane-based wearable organic electrochemical device for noninvasive cortisol sensing is published in the journal Science Advances.
Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru based on Stanford University: Wearable device from Stanford measures cortisol in sweat.