Super Permeable Wearable Electronics Enable Long-Term Biosignal Monitoring

Wearable electronics have become integral to enhancing health and fitness by offering continuous tracking of physiological signals over extended periods. This monitoring is crucial for understanding an individual's health, predicting diseases early, tailoring treatments, and managing chronic conditions more effectively. Yet, challenges like sweat or air influencing long-term signal stability have hampered their performance. Now, new super wearable electronics that are lightweight, stretchable, and also boast a 400-fold increase in sweat permeability could pave the way for reliable long-term monitoring of biosignals by biomedical devices.

Scientists at City University of Hong Kong (CityUHK, Hong Kong) have developed a universal method for creating super wearable electronics that enable gas and sweat permeability. This breakthrough overcomes a significant hurdle for wearable medical devices by ensuring that monitoring of vital signs remains uninterrupted and comfortable, even in the presence of sweat. The team's method is based on material processing, device design, and system integration, resulting in wearable electronics that incorporate a nature-inspired three-dimensional liquid diode (3D LD). This design allows liquids to flow spontaneously in a specific direction, thanks to surface structures that encourage the movement of sweat away from the skin.

Image: The permeable wearable electronics developed for long-term biosignal monitoring (Photo courtesy of CityUHK)

By applying a 3D spatial liquid manipulation approach, the researchers have managed to build fully integrated permeable electronics that match the circuitry and functionality to state-of-the-art wearable devices, enabling extraordinary breathability. The 3D LD does not depend on unique materials alone but also adopts an in-plane liquid transport layer termed horizontal liquid diode. In the study, the device showed that it can transport sweat from the skin 4,000 times more effectively than produced by the human body. This guarantees seamless monitoring even during sweating conditions, thereby resolving the issue of signal disruption due to sweat accumulation at the device-skin interface. Thanks to its thin, lightweight, soft, and stretchable features, the device also showed exceptional compatibility with the human body by adhering strongly to the skin. The study also revealed a comfortable and stable interface between the device and the skin, resulting in high-quality signals. Currently, the team is conducting advanced clinical trials to validate the effectiveness of their technology in real-world scenarios.

“Our findings provide fluid manipulation and system integration strategies for the soft, permeable wearables,” said CityUHK Professor Yu Xinge who led the study. “We have successfully applied this technology to both advanced skin-integrated electronics and textile-integrated electronics, achieving reliable health monitoring over a weeklong duration.”

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