Gerhard.Nebe-von-Caron at Unilever.com
Wed Aug 26 11:37:07 EST 1998
Whilst the blue light can excite certain intracellular
molecules the low energy and exposure time makes it unlikely
to take an effect unless the cells are already damaged prior
to sorting. I have done similar experiments in order to
test the potential injury inflicted by the laser on
heat-injured bacteria that are quite fragile. I sorted
cells either based on the red HENE or the blue Argon laser
with similar recovery, thus deciding the wavelength not to
be a problem.
Form the literature there is quite some evidence of the
effect of cell acceleration on the viability of cells which
can be affected by nozzle diameter and differential
pressures, but they all seem to be not as dramatic in your
case. However you also might consider flow restrictions in
the system that might cause a cell squeeze effect. You
might also want to look at the possibility of sheath that
flows back into your sample or potentially bleach from the
disinfection run if performed before the sort, so you should
consider comparing the viability of the cells in the sample
tube compared to the cells in the sorted tube.
I assume you compared the 'unsorted' cell viability also
after diluting the cells in your sheath medium at the same
temperature as your sort conditions, as that might have a
substantial effect on their survival.
______________________________ Reply Separator _________________________________
Subject: sort viability
Author: cozens at postoffice.utas.edu.au at INTERNET
Date: 24/08/1998 18:36
Thanks for all the helpful responses so far concerning my problem
with obtaining viable sorts. Perhaps this additional information may be of
The cells I am sorting are murine splenic lymphocytes. Directly post sort
their viability is 80% (tyrpan blue).
Flow details: Coulter Elite ESP sorter, power 15mW air cooled argon, 100um
nozzle, sheath straight PBS, sort speed @3000/sec, pressure @11 psi
I've done several test sorts and my results indicate an increase in
viability with the laser off (collecting everything) although viability
still remains low. Is there a possibility that laser power could be
affecting my cells in some way?
The concerned student, James.
Mark A Cozens
Division of Pathology
University of Tasmania
ph 03 62264828
fax 03 62264833
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