Efficient measurement of airborne viable viruses using the growth-based virus aerosol concentrator with high flow velocities

Growth tube collectors (GTCs) are used to sample virus aerosols because of their superior viable virus recovery among air samplers. However, a major limitation of such samplers is that they operate at low flow rates compared to many inertia-based air samplers. Herein, we demonstrated efficient measurements of airborne MS2 and T3 viruses using a GTC that can implement high flow velocities for higher flow rates per tube, which we refer to as the growth-based virus aerosol concentrator (GVC), via qPCR and the plaque assay technique. The GVC exhibited a flow rate of up to 6 L/min, where the average sampling flow velocity was 5.09 m/s, 22 times higher than those used in the GTCs, for a single tube with a diameter of 5 mm. The count median diameter of the size increased particles at the exit of the initiator was measured to be 1.44 mu m at 6 L/min, considerably smaller than those observed in conventional GTCs. Nevertheless, the measurement of airborne MS2 and T3 viruses using the GVC showed a high concentration (high enrichment ratio of 109,458 at 10-min sampling) of viruses in a sampling medium, with a high viable virus percentage (> 90%) and physical collection efficiency (> 90%) at 6 L/ min, which shows the potential for rapid on-site detection of airborne viruses.

Automated summary

This study demonstrated the efficient measurement of airborne MS2 and T3 viruses using a new growth tube collector called the growth-based virus aerosol concentrator (GVC). Compared to traditional GTCs, the GVC has higher flow rates and smaller particle diameters, resulting in high concentration of viruses in the sampling medium. The GVC shows potential for rapid on-site detection of airborne viruses.