Ultrarapid Collection of High-Concentration Viral Samples from Small-Volume Exhaled Breath for Respiratory Virus Surveillance

Rapid and sensitive detection of airborne respiratory viruses from exhaled breath is essential for early diagnosis and outbreak control, yet current strategies suffer from low capture efficiency and sample dilution. Here, we present a fully automated, noninvasive Phase-change Drywall Cyclone Sampler (PDC-sampler), which integrates phase-change condensation with a CFD-optimized cyclone gas-liquid separator. This design rapidly condenses viral aerosols─particularly those <5 μm─into microdroplets and directs them into a stable spiral liquid stream, thereby enhancing capture efficiency and producing a small-volume, high-concentration liquid sample. The collected condensate is directly coupled to a microfluidic RNA-release chip, enabling on-chip viral RNA lysis. From a single tidal exhalation (∼0.5 L), the system generates ∼20 μL of high-concentration RNA lysate in 10 s of on-device processing (sample-to-lysate), directly compatible with nucleic acid detection. Combined with ddPCR, it achieves detection limits as low as 5-9 copies per exhalation for pathogens including SARS-CoV-2 and H1N1 influenza. This ultrarapid, small-volume, sample-to-result workflow provides a scalable, field-deployable solution for point-of-care diagnosis and real-time respiratory virus surveillance.