Film-rupture actuated pump-free capillary enrichment for near-source airborne sampling

With the persistent threats from severe respiratory diseases and airborne pollutants, billions of people worldwide lack timely access to essential diagnostic services, particularly in low-resource regions where laboratory infrastructure is scarce. Conventional pump-suction airborne samplers face challenges including cost, power dependency, and unavoidable analyte loss in complex systems. Here, we demonstrate a film-rupture actuated capillary enrichment (FACE) airborne sampler that replaces external suction with inherent surface-energy release of a rupturing liquid film, unifying collection, recovery, and readout into a single, pump-free event. Guided by in situ observations of a coiled-butterfly-proboscis "film-rupture" drinking mode and a biomimetic ring-and-capillary design, the FACE sampler couples a suspending liquid film for high-area collection with film-rupture-augmented capillary transport for autonomous recovery. A film-rupture augmented Washburn model and an "empty-effect" design criterion with optimized double-outlet, Tesla-guided architecture quantitatively explain submillisecond triggering (<0.5 ms), high-velocity enrichment (>50 mm s^-1), and complete evacuation with near-zero residue. Built from low-cost polymers (~$0.12), the pump-free and portable FACE sampler with a robust liquid film is demonstrated and adapted for diverse targets, scenarios, and detection methods. In the near-source demonstration, the FACE sampler outperforms the pump-suction device in improving sampling efficiency and minimizing dilution, enabling visual detection at two orders of magnitude lower analyte levels. We envision broad applications of the FACE airborne sampler in environmental monitoring, agricultural safety, and public healthcare, providing a sustainable and scalable approach toward equitable access to high-performance point-of-care technologies.