When doing transfection experiments, we routinely determine viability of
the samples by FACS on the basis of FCS vs SSC profiles (these are
non-adherent cell lines). Someone in the lab has just done an
experiment where they checked the viability of each sample by trypan
blue exclusion by light microscopy as well as by FACS. To her surprise
viabilities were much higher by trypan blue than by FACS (eg 60% vs 17%,
respectively).
One way to explain this is that maybe non-viable cells break up so one
single non-viable cells becomes several "events" in the non-viable area
of a FACS plot, leading to a disproportionate number of non-viable vs
viable events. Does anyone else have any suggestions, or seen this
disceprancy themselves? Which is more accurate? I would always have
said FACS but now I'm not so sure.
Thanks in advance,
Michelle
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Michelle Miller
JJR Labs
GPO Box 3331
Sydney NSW 2001
Australia
02 360 9377 (Ph) 02 360 9813 (fax)
jjph13mm@angis.su.oz.au