Bioinspired Kirigami Origami Card for Spray Collection toward Facile Airborne Viruses Monitoring

There is an urgent need for efficient airborne virus monitoring to proactively cut off transmission sources in the public. However, infected respiratory sprays can remain stable in the airborne aerosols, and the sampling of airborne viruses has low efficiency. In this work, inspired by the cactus conical leaves and redbud venation, we propose an approach for the capture of airborne virus and in situ detection. A paraffin kirigami with cactus cone-shaped spine units arranged to mimic leaf veins was designed to integrate with electrochemical monitoring as an origami card. With the combined effect of Laplace pressure, gravity assistance, leaf vein-mimicking structure, and aerodynamic vortices induced by the assembly of the origami card, the paraffin kirigami card demonstrates excellent ability to collect virus-containing sprays from air and facilitate directional transport and aggregation. The peak fog harvesting rate reaches 5424.2 mg/cm²/h, demonstrating exceptional efficiency in atmospheric droplet capture. A triad electrode system is accommodated at the root of the spray collector to monitor airborne virus in the collected droplets. The paraffin kirigami card achieves a low limit of detection (LOD) of 0.10776 copies/mL and shows a good linear relationship between the impedance and influenza A (H1N1) virus concentration. Validation using thrombin as a model target analyte confirmed the system's integrated capability for rapid collection, identification, and sensitive detection of viruses. This cactus-inspired paraffin kirigami card demonstrates significant potential for real-time, in situ airborne virus collection and detection, contributing to efforts to control the spread of viruses.