Spiral Microchannel-Based Chip for Virus Monitoring Using Localized Air Sampling

Detecting airborne viruses is important for preventing infectious disease outbreaks, but conventional workflows require aerosol collection and downstream processing. Here, we developed a proof-of-concept spiral microchannel chip integrating aerosol capture and on-chip nucleic acid amplification for localized virus detection. Peripheral microwells along the outer turns served as capture sites and reaction reservoirs, while an upstream humidification pool reduced evaporation under airflow. During aspiration, curvature-induced centrifugal bias and Dean-vortex secondary flow promoted aerosol transport toward the wells. Numerical simulations and fluorescent bead experiments provided complementary evidence of particle transport and deposition near the peripheral wells. At an airflow rate of 50 mL/min, the humidification pool extended the approximate drying time from 10 to 30 min. Amplification-accessible virus-derived DNA was detected directly in the wells using recombinase polymerase amplification (RPA) with an exonuclease-cleavable fluorescent probe. End-to-end operation was demonstrated using nebulized bacteriophage T2 aerosols, with localized fluorescence observed in multiple wells after incubation at 40 °C for 30 min, without intermediate sample transfer or nucleic acid extraction. By integrating capture, humidification, and amplification on a single chip, this approach reduces operational complexity and reagent handling. These findings demonstrate the feasibility of compact, extraction-free aerosol detection and support further development toward source-proximal and distributed airborne-virus monitoring.