Wearable sensors that track heart rate or steps are popular fitness merchandise. However, in the future, working up a good sweat might provide useful details about an individual’s health. Now, researchers reporting in ACS Utilized Materials & Interfaces have developed a headband that measures electrolyte ranges in sweat. And unlike many earlier sweat sensors, the system can heal itself when cut or scratched during exercise.
Human sweat contains biochemical markers, such as metabolites, electrolytes, and heavy metals, that may point out a person’s well being and even help diagnose some ailments. In recent years, scientists have engineered sweat sensors in the form of patches, bandages, and tattoos; however, their performance might be impaired by natural actions such as strolling, running, leaping, or throwing. Also, if the sensors turn out to be scratched or broken, which may happen during exercise, they usually can’t be repaired.
Sung Yeon Hwang, Jeyoung Park, Bong Gill Choi and colleagues needed to create a wearable sweat sensor that might stand up to vigorous training and quickly restore itself if damaged.
To make their self-healing sensor, the researchers coated carbon fiber thread electrodes with a citric acid-based polymer.
When cut, the threads shortly rejoined through the hydrogen bonding of the polymer. They sewed the threads, which may detect potassium and sodium ions, into a headband and added a wireless digital circuit board that might switch data to a smartphone.
A human volunteer wore the scarf while exercising on a stationary bike, and the sensor accurately tracked the electrolyte concentrations in their sweat over 50 minutes of exercise. During cycling, the researchers lower the sensor threads with scissors, and the threads healed and returned to regular operation in 20 seconds.