clumping
* There are several tips for preventing clumping. Using EDTA at
up to 5mM concentrations may help prevent cation dependent cellcell adhesion. Do not keep the cells at too high a concentration
either (no more than 5-6 million/ml). Likewise using Ca/Mg++
free buffers will also help. Remember adding serum to your
buffers will replace the Ca/Mg++ so if you need a
protein support try using BSA instead. If your cells are
clumping due to dying cells, the addition of DNAse II (10u/ml)
may help. Of course you could filter your sample through a nylon
mesh but the important thing is to
prevent clumping so you do not lose too many cells.
* I use 2-5% BSA to coat the cells. I think it also helps
protect the cells,
when sorting, from the degassing effects at the
nozzle exit. If they are really clumpy I add some DNAse
[assuming the cells are alive].