(Video courtesy of UC Berkeley.)

A new wearable perspiration sensor can provide healthcare professionals with real-time measurements of patients’ metabolites and electrolytes.

Worn as wristbands or headbands, the sensors can transfer data to a smartphone in real time. Health monitoring wearables are nothing new, but this device is the first fully-integrated electronic system for continuous, non-invasive monitoring of the key biochemicals in sweat. This allows problems like fatigue, dehydration and dangerously high body temperatures to be identified quickly.

“Human sweat contains physiologically rich information, thus making it an attractive body fluid for non-invasive wearable sensors,” said principal investigator Ali Javey, a professor of electrical engineering at UC Berkeley.

“However, sweat is complex and it is necessary to measure multiple targets to extract meaningful information about your state of health," Javey continued. "In this regard, we have developed a fully-integrated system that simultaneously and selectively measures multiple sweat analytes and wirelessly transmits the processed data to a smartphone. Our work presents a technology platform for sweat-based health monitors.”

Testing the Sweat Sensors

The flexible circuit board contains five sensors, which monitor skin temperature, the metabolites lactate for muscle fatigue and glucose and the electrolytes sodium and potassium.

Since measurements of glucose and lactate depend on temperature, the skin temperature measurement is used for calibration. The wireless printed circuit board made from silicon components contains more than ten integrated circuit chips to measure sensor readings.

An app developed by the researchers syncs data from the sensors to mobile phones.

The sensors were tested on dozens of volunteers in indoor and outdoor exercise activities. The lucky ones performed short bursts of exercise, while others were subjected to much longer exercise routines.

Improving Health Monitoring

The flexible sensors have potential applications in medicine for monitoring body fluids indicative of illness or injury. Further studies and changes to the device, such as added sensors for different physiological measurements, can bring about new studies and advancements in how the body is monitored.

“We can easily shrink this device by integrating all the circuit functionalities into a single chip,” said Sam Emaminejad, a post-doctoral student in Javey’s lab. “The number of biochemicals we target can also be ramped up so we can measure a lot of things at once. That makes large-scale clinical studies possible, which will help us better understand athletic performance and physiological responses to exercise.”

For more information, visit the UC Berkeley website.