Scientists Design First-Of-Its-Kind Thread-based Wearable Sweat Sensors To Monitor Health

Real-time monitoring of electrolyte and metabolite levels could be used to diagnose and monitor diseases, said a new study.

The experts at Tufts University have designed a first-of-its-kind flexible electronic sensing patch that could be sewn into clothing to analyze a person’s sweat for multiple health markers. The newly designed patch can be used to diagnose and monitor not only acute and chronic health conditions but also athletic or workplace performances.

The new device consists of special sensing threads, electronic components alongside wireless connectivity for real-time data acquisition, storage, and processing.

Existing health monitors usually track heart rate, temperature, walking distance, sleep, glucose levels, and other measurements. But a more detailed understanding of a person’s health, stress, and performance is crucial for medical data collection or high-performance athletic/military applications.

Precisely, metabolic markers like electrolytes and other metabolites could be a better indicator of human health for accurate assessment of chronic health conditions, athletic performance, workplace safety, and clinical diagnosis, said the researchers in their paper published in the journal NPJ Flexible Electronics.

The new patch device

It performs real-time measurements of important health biomarkers present in sweat including sodium and ammonium ions (electrolytes), lactate (metabolite), and pH levels. The device is so versatile that it incorporates a wide range of sensors that are capable of tracking nearly every important health biomarker present in a person’s sweat. The measurements can aid in useful diagnostic applications.

The device measures several health biomarkers found in sweat such as:

• Sodium which could indicate the hydration status and electrolyte imbalance in the body
• Lactate levels could indicate muscle fatigue
• Chloride ion levels could diagnose and monitor cystic fibrosis
• Cortisol-- a stress hormone could assess one’s emotional stress, metabolic and immune functions

Athletes could use this device to monitor a wide range of health markers during physical exertion and predict performance peaks or declines during a competition. It contains flexible threads coated with conductive inks which makes it possible to incorporate the sensors into clothing. For instance, lactate can be detected by coating a thread with an enzymatic sensing material with the enzyme lactate oxidase. And a pH sensing thread will be coated with polyaniline – an electrically conducting polymer that responds to acidity.

"Sweat is a useful fluid for heath monitoring since it is easily accessible and can be collected non-invasively. The markers we can pick up in sweat also correlate well with blood plasma levels which makes it an excellent surrogate diagnostic fluid," EurekAlert quoted the study’s lead author Trupti Terse-Thakoor.

Their new sensor patch is only a part of a larger strategy to design completely flexible thread-based electronic devices that could be woven into a fabric.