Researchers from Stanford University developed a device capable of measuring cortisol from sweat.
Cortisol is a hormone that fluctuates naturally throughout the day and is responsible for stress responses. Current lab methods to measure cortisol levels require several days for results. Such delay often leads to medical conditions that might be different from when the test was taken. Now a research led by Onur Parlak, a post-doctoral scholar in the Salleo lab at Stanford University, developed a device that when applied directly to the skin, wicks up sweat to measure the cortisol levels a person is producing. The report of this wearable sensor was published in the journal Science Advances on July 20, 2018. Measuring cortisol provides the extent of emotional or physical stress in research subjects and can aid in determining the functioning of adrenal or pituitary gland.
The researchers built a stretchy and rectangular sensor around a membrane that specifically binds only to cortisol. It sucks in sweat by sticking to the skin through holes in the bottom of the patch. The sensors detect the backed up charged ions of sodium or potassium that pass through the membrane unless they are blocked by cortisol. Furthermore, a waterproof layer on the sensor protects the patch from contamination. A user needs to sweat and apply the patch and a device connected to the patch gives the result of the cortisol levels in seconds. It was observed that the device measured up to the gold standard clinical test in the lab. It was later tested on two volunteers who ran for 20 minutes with the patches on their arms. The results obtained in the real world experiment were similar to those in the lab. The researchers stated that the sensor appears to work as designed. However, they urged that further trails and study is required for more reliable and accurate results and to make sure that the patch is reusable.