Turbosort sterility

Richard D. Schretzenmair rds at mail.MED.UPENN.EDU
Mon Dec 10 15:45:23 EST 2001

Hello Mike

We have been using pall filters on our FACSVantage SE with Tubosort for
about 18 months now with only rare instances of sort contamination. We sort
with pressures up to 45 psi We have left the pall filter on for up to six
months without problems. We check for sterility daily by sorting into
nutrient broth.

When we install a new pall filter we add a couple of liters of 70& ethanol
to the sheath tank and run it through the whole system (including filter)
for at least a hour to overnight. We then rinse with sterile water followed
by sheath fluid. We try to keep the sheath tank sterile at all times. The
outside of the tank is washed with ethanol before opening and filled only
with sterile filtered sheath fluid (PBS with Hepes). We prepare 10 liters of
sheath fluid at a time using Millipore Sterivac 0.22µm filters into
autoclaved 1 gallon containers.

To prevent bacteria from working their way in from the front end of the
system we do a 10-15 minute hydrogen peroxide rinse each morning. We
disconnect the quick release fitting after the pall filter and cover the
exposed end with a ethanol filled latex finger cut off a glove. Attach a
quick release fitting to a syringe. We then push 50cc of 5% hydrogen
peroxide through the system, making sure to set the fluidics control knob to
all it's positions. Also make sure the syringe used to chase air out fills
with peroxide. The idea is to get the peroxide in contact with all surfaces
after the pall filter. When done just reconnect the pall filter and rinse
till the peroxide is cleared.

Good Luck

Rich Schretzenmair
Cancer Center Flow Cytometry Shared Resource
University of Pennsylvania

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