One problem with sensors that derive information from sweat is that the patient being tested has to actually sweat. Oftentimes this entails exertion or room temperatures that run the gamut from impractical to unsafe. But thanks to Eccrine Systems Inc., testing sweat may soon become both easier and safer.
 
Founded by University of Cincinnati professor Jason Heikenfeld, Eccrine Systems has developed a device that can stimulate sweat glands on a small, isolated patch of skin. It does so using chemicals, allowing the patient to remain relaxed and comfortable. And according to a study in the journal Lab on a Chip, the sensors can also make predictions on how much a given patient will sweat, allowing researchers to better understand the hormones and chemicals involved in the process.
 
Analyzing sweat can serve as a noninvasive alternative to blood analysis, which entails lab work and often prohibits the blood monitoring activities from being continuous and in real-time. Sweat, by contrast, provides a means of monitoring health that’s easier and more convenient, both for the patient and the caregiver.
 
Researchers in the study tested the sensors in three different ways: alone, with memory foam to make the sensor adhere more flushly to the skin, and in conjunction with a small amount of the chemical carbachol, which was driven into the upper layer of the skin using a small electrical current in a process known as iontophoresis. Carbachol stimulates sweat glands without causing discomfort.
 
Using a dye that was sensitive to pH changes, researchers determined that sweat glands were stimulated evenly across the area covered by the sensor. The study called it a “significant leap forward” in sweat sensing technology.
 
One of the potential advantages in using these sensors is in measuring the stress hormone cortisol, which can help athletes determine when they may be pushing their bodies too hard. It can also help determine whether a professional is facing severe mental stress.