Stanford University have developed a wearable capable of measuring cortisol levels from the users sweat which determines stress. The paper published in Science Advances outlines the early development and use of the technology by the researchers.
"We are particularly interested in sweat sensing, because it offers noninvasive and continuous monitoring of various biomarkers for a range of physiological conditions. This offers a novel approach for the early detection of various diseases and evaluation of sports performance.”
Onur Parlak, a post-doctoral scholar in the Salleo lab and lead author of the paper
The researchers developed a new type of stretchy and flexible sensor called MS-OECT which selectively senses the cortisol levels in the human stress. It includes sensors that can bind to the cortisol molecules while permitting others to pass through its membrane.
“We introduce the integration of an electrochemical transistor and a tailor-made synthetic and biomimetic polymeric membrane, which acts as a molecular memory layer facilitating the stable and selective molecular recognition of the human stress hormone cortisol. The sensor and a laser-patterned microcapillary channel array are integrated in a wearable sweat diagnostics platform, providing accurate sweat acquisition and precise sample delivery to the sensor interface.”
But the technology isn't just for telling someone that they are stressed out, it's also for giving a lot of insight into a patients condition and health. It is thought that this technology will be used in the future to better inform users in their own homes, rather than seeing a doctor, and informing them how to improve their on healthcare.
“Stress plays an important role in the overall health of a patient; when under stress, the adrenal gland releases cortisol and adrenaline into the bloodstream. Increased levels of cortisol have a detrimental effect on the regulation of various physiological processes such as blood pressure, glucose levels, and carbohydrate metabolism, and sustained stress can disrupt homeostasis in the cardiovascular, immune, renal, skeletal, and endocrine systems, leading to development of chronic diseases. Therefore, continuous monitoring of cortisol levels in bodily fluids has great relevance in maintaining healthy physiological conditions.”
Researchers tested the prototype on a small number of volunteers against the ELISA method which is the current recommended method of testing. The results found the device had a strong positive correlation (relative standard deviation of five percent for the two measurements).
“In summary, we have demonstrated the integration of an artificial receptor as a biomimetic polymeric membrane for stable and selective molecular recognition using OECTs to produce a wearable sweat diagnostics platform for real-time analysis of the human stress hormone cortisol,”
The team of researchers isn't the only team looking to analyse sweat. Eccrine Systems announced it had developed a device which can stimulate a sweat gland on a small patch of skin. Its sensors can then make predictions on how much sweat the patient will produce allowing researchers to understand the hormones and chemicals in the process.
However, with this new wearable technology the design principles allow for the selective detection of other molecules & hormones. The future research will be aimed at miniaturizing the device, improving sensing interfaces, data evaluation and harvesting energy directly from bodily fluids to power the device.