Measuring containment of viable infectious cell sorting in high-velocity cell sorters

With the advent of high-speed sorters, aerosols are a considerable safety concern when sorting viable infectious materials. We describe a four-part safety procedure for validating the containment.

This procedure includes aerosol containment, physical barriers, environmental controls, and personal protection. The Aerosol Management System (AMS) produces a negative pressure within the sort chamber, where aerosols are forced through a HEPA filter. Physical barriers include the manufacturer's standard plastic shield and panels. The flow cytometer was contained within a BSL-3 laboratory for maximum environmental control, and the operator was protected by a respiratory system. Containment was measured by using highly fluorescent Glo-Germ particles under the same conditions as the cell sort.

Escaping aerosols were vacuumed for 10 min onto a glass slide and examined. With the AMS active and the cytometer producing the maximum aerosols possible, Glo-Germ particles remained within the sort chamber. Measurements taken directly outside the door averaged fewer than one particle per slide, and those taken at 2 ft away and on top of the sorter were completely negative.

With this monitoring system in place, aerosols can be efficiently measured, thus reducing the risk to the operator while sorting viable infectious cells.