Medical News Observer

Key Points:

• The sweat monitoring ‘band-aid’ combines flexible photonics and hydrogel-encapsulated liquid crystal droplet lasers to measure sweat biomarkers like lactate, glucose, and urea.
• The device can detect biomarker fluctuations down to 0.001 millimeters, surpassing current technologies in sensitivity.
• Data from the sensors are transmitted to a mobile app, facilitating easy and practical health monitoring. The device has the potential to detect a broader array of substances in the future.

Scientists from Nanyang Technological University (NTU) in Singapore have developed an innovative ‘band-aid’ that can measure body biomarkers through sweat, providing a new, non-invasive method for health monitoring.

Flexible Photonics

Flexible photonics presents the potential for creating wearable sensors by combining the benefits of flexible materials and photonic sensing elements. Despite recent advancements with optical resonators enhancing sensor sensitivity, monitoring multiple physiological signals directly on human skin remains challenging due to the complexity of biological signals and tissue interfaces.

Sweat monitoring ‘Band-aid’

Researchers have developed a functional thin-film laser to address these challenges. The laser encapsulates liquid crystal droplet lasers in a flexible hydrogel and monitors metabolites in human sweat, such as lactate, glucose, and urea. The mobile application analyzes and translates this data. This opens up a world of possibilities for comfortable and practical health monitoring.

This system uses a three-dimensional cross-linked hydrophilic polymer layer to facilitate molecule penetration from human tissue. It generates strong light-matter interactions at the interface of whispering gallery modes resonators. The hydrogel and cholesteric liquid crystal microdroplets are specially modified for high sensitivity and selectivity.

The NTU researchers highlight that their device can detect fluctuations in biomarker levels down to 0.001 millimeters, surpassing the sensitivity of current technologies. This capability allows for comprehensive health tracking, including both high and low ranges of biomarkers, which is particularly beneficial for diabetic patients.

Future

As proof of concept, this technology shows promise in wavelength-multiplexed sensing on human skin. It marks a significant advancement in developing wearable and functional microlasers for healthcare applications. The NTU team plans to refine the microlaser sensors to detect more substances, including drugs and other chemicals in sweat.

Reference

Nie, Ningyuan, Xuerui Gong, Chaoyang Gong, Zhen Qiao, Ziyihui Wang, Guocheng Fang, and Yu-Cheng Chen. “A Wearable Thin-Film Hydrogel Laser for Functional Sensing on Skin.” Analytical Chemistry 96, no. 22 (June 4, 2024): 9159–66. https://doi.org/10.1021/acs.analchem.4c00979.