Wearable hydrogel-based health monitoring systems: A new paradigm for health monitoring?

With the ability to dynamically and continuously measure health indicators and the potential to offer early warning messages about physical diseases, wearable health monitoring systems have garnered significant attention. However, with the increasing demand for diversified monitoring, the shortcomings of wearable health monitoring systems in terms of environmental adaptability, data transmission, data analysis, and timely feedback continue to surface, which seriously hindering their development. Today's wearable health monitoring solutions require not only excellent sensing performance but also exceptional environmental adaptability and biocompatibility of sensing materials. Therefore, hydrogels with adjustable multifunctionality, multi-stimulus sensitivity, and biocompatibility are considered among the best sensing materials for wearable health monitoring systems. In this review, we explore the correlation between the multifunctionality of hydrogels and the environmental adaptability of health monitoring systems at a fundamental level. Furthermore, with the ambition of achieving comprehensive monitoring of health indicators, we discuss emerging technologies that enable multimodal/multi-channel wireless transmission and intelligent analysis of data. Finally, for effective feedback on health indicators, we describe integrated and closed-loop solutions that harmonize the various components. Accurate, intelligent, and reliable real-time monitoring of health indicators will have a significant impact on our daily lives.