Air-VELoCheck: A Novel Airflow Velocity Assay to Rapidly Monitor the Integrity of the Aerosol Evacuation System Within a Flow Cytometer

Introduction: Most high-speed cell sorters rely on droplet generation technology to create statically charged, particle containing droplets triaged at high throughput based on distinct characteristics of the targets. Normally, aerosols generated through the droplet breakoff process are constantly removed as waste or pulled away from the operator by the negative pressure dynamics created by an Aerosol Evacuation System (AES). However, if the AES integrity has been compromised, aerosols produced by a stream diversion event may potentially expose the environment and the operator to any potentially hazardous material that is being sorted. Standard methods to validate the integrity of the AES rely on the collection of aerosolized beads that escape the front of a sorter during a simulated stream diversion event. Although much improved compared with previous versions, the assay still requires 1–2 h to perform. Methods: We use a simple airflow meter in conjunction with an original set of 3D printed holders and a hot wire anemometer to measure vacuum created by the AES at two locations within the flow cytometer. Results: Here, we describe Air-VELoCheck, an airflow velocity assay to monitor AES integrity. The assay was validated against the standard aerosol containment assay and takes <15 min to perform, representing an approximate 75–88% reduction in assay time. Conclusions: Our findings support the need to accelerate efforts toward the integration of real-time monitoring of AES performance, particularly for laboratory operations requiring biosafety containment, to quickly diagnose alterations in aerodynamics that can be confirmed using other orthogonal assays.