Toralf Kaiser

Jenny Kirsch¹, Alexander Wolf¹, Daniel Kage¹, Konrad v. Volkmann²,  Toralf Kaiser¹

¹German Rheumatism Research Centre Berlin (DRFZ) - Flow Cytometry Core Facility, Charitéplatz 1 (Virchowweg 12), 10117 Berlin, Germany

² APE Angewandte Physik und Elektronik GmbH, Plauener Straße 163-165 / Haus N, 13053 Berlin,   Germany

Various biohazardous materials such as cells, bacteria, or viruses may be present in flow cytometer waste. Therefore, the waste is chemically or physically inactivated through complex processes to prevent environmental impact. Inactivating waste from multiple cytometers is a time-consuming task for core facilities.

In addition, aseptic cell sorting is challenging, especially when a cell sorter is not operated in a sterile environment. Therefore, a regular cleaning procedure is required to prepare a sorter for aseptic cell sorting by flushing the fluid system with sodium hypochlorite or ethanol. However, this procedure is time-consuming and, most importantly, the researcher can never be sure that the cleaning process was successful. In addition, residues of cleaning agents in the fluidic system are toxic to the cells.

Here we present a method based on a UV-C reactor for flow-through inactivation of the sheath and waste fluid. The reactor, which contains 4 UV-C LEDs with an emission wavelength of 265 nm, has been used on four different cell sorters and analyzers. Using the reactor, we were able to decontaminate sheath and waste fluids contaminated with bacteria or cells to enable antibiotic-free long-term cell culture or to avoid time-consuming decontamination procedures.