Bioinspired Wettability Engineering Enables Efficient Exhaled Breath Condensate Harvesting for Wearable Respiratory Monitoring.

Efficient collection of exhaled breath condensate (EBC) remains a major challenge for wearable respiratory monitoring because limited sample yield often compromises analytical sensitivity and signal reliability. Herein, we report a smart bioinspired mask that enables efficient EBC harvesting through hybrid wettability engineering. Inspired by the hydrophilic-hydrophobic patterns on the Namib Desert beetle's back and the hierarchical transport networks of leaf veins, a hybrid wettability pattern consisting of hydrophilic star-shaped domains and vein-like microchannels is constructed on a superhydrophobic substrate through a facile three-step fabrication process. This design enables coordinated droplet nucleation, coalescence, directional transport, and centralized collection of EBC. Experimental results demonstrate that this mask achieves a high EBC collection rate of 139.8 μL min-1. Integrated with a flexible electrochemical sensor array, the wearable platform further enables real-time multiplexed analysis of representative EBC biomarkers with high sensitivity and reliability. Continuous human monitoring demonstrates the capability of the system for dynamic tracking of physiological signals under real-world conditions. This work not only provides a versatile bioinspired structural design strategy for efficient regulating interfacial condensation and transport but also provides a promising platform for wearable respiratory analysis devices toward personalized health care.