Wearable
biosensors for sweat-based analysis are gaining wide attention
due to their potential use in personal health monitoring. Flexible
wearable devices enable sweat analysis at the molecular level, facilitating
noninvasive monitoring of physiological states via real-time monitoring
of chemical biomarkers. Advances in sweat extraction technology, real-time
biosensors, stretchable materials, device integration, and wireless
digital technologies have led to the development of wearable sweat-biosensing
devices that are light, flexible, comfortable, aesthetic, affordable,
and informative. Herein, we summarize recent advances of sweat wearables
from the aspects of sweat extraction, fabrication of stretchable biomaterials,
and design of biosensing modules to enable continuous biochemical
monitoring, which are essential for a biosensing device. Key chemical
components of sweat, sweat capture methodologies, and considerations
of flexible substrates for integrating real-time biosensors with electronics
to bring innovations in the art of wearables are elaborated. The strategies
and challenges involved in improving the wearable biosensing performance
and the perspectives for designing sweat-based wearable biosensing
devices are discussed.