Innovative Wearable Sweat Sensor Predicts Muscle Fatigue

Tokyo University of Science Researchers have designed a novel sweat sensor.

Image credit: hippopx (Creative commons)

A research team from the Tokyo University of Science (TUS) has designed a novel sweat sensor for continuous monitoring of lactate, which is helpful for predicting muscle fatigue.

The work, published online in ACS Sensors on June 15, 2023,describes the use of a technique called "heat-transfer printing" to fix a thin, flexible chloride ion sensor onto a textile substrate. The study was co-authored by Dr. Masahiro Motosuke, Dr. Tatsunori Suzuki, Dr. ShinyaYanagita, and Dr. Takahiro Mukaimoto of TUS.

"The proposed sensor can be transferred to fibersubstrates, and thus can be incorporated into textiles such as T-shirts,wristbands, and insoles," explains Dr. Shitanda. "Further, healthindicators such as chloride ion concentration in sweat can be measured by simply wearing them."

The heat-transfer printing approach offers several advantages. For one thing, the sensor is transferred outside of the piece of clothing, which prevents skin irritation. In addition, the wicking effect of the textile helps spread the sweat evenly between the electrodes of the sensor, creating a stable electrical contact. Moreover, printing the sensor on a flat surface and then transferring it prevents the formation of blurred edges that commonly occur when printing directly onto a textile.

The researchers carefully selected the materials and electrochemical mechanisms of the sensor to avoid risking an allergic reaction for the wearer. After developing the sensor, they conducted various experiments using artificial sweat to verify its accuracy in measuring chloride ion concentration. The change in the electromotive force of the sensor was −59.5mTV/log CCl−. Additionally, it displayed a earnest response and a linear relationship with the concentration range of chloride ions in human sweat. Moreover, no other ions or substances typically present in sweat were found to interfere with the measurements.

Related: Wearable Sweat Sensor Detects Inflammation

Lastly, the team tested the sensor on a volunteer who exercised on a static bicycle for 30 minutes, by measuring their perspiration rate, chloride ion levels in blood, and saliva osmolality every five minutes to compare with the data previously gathered by the sensor. The proposed wearable sensor could reliably measure the concentration of chloride ions in sweat.

The sensor can also transmit data wirelessly, making it useful for real-time health monitoring. "Since chloride is the most abundant electrolyte in human sweat, measuring its concentration provides an excellent indicator of the body's electrolyte balance and a useful tool for the diagnosis and prevention of heat stroke," remarks Dr. Shitanda.

This research thus demonstrates the potential of using wearable ion sensors for the real-time monitoring of sweat biomarkers, facilitating personalized healthcare development and athlete training management.

Sam Draper
July 25, 2023

Innovation of the Month

Do you want to discover more, visit the website
Visit Website

Other news

Accelerating the Production of Soft Robots

New method for manufacturing liquid-metal-based soft and stretchable electronics has been developed.

Facebook and Ray Ban Launch Next-Gen Smartglasses Ray-Ban Stories

Facebook, Inc. and Ray-Ban has teamed up to launch the next generation of smart glasses ...

Sweat Powered Wearable Devices May Hit The Market Very Soon

Wearables have been around for a few years but their popularity, especially in the form....

NewsTechnologyWT | Member Oura Ring’s New Feature ‘Moment’ Tracks Your Meditation

Oura ring now has a new feature called Moment, which can track your meditation.
Discover more