RE: Sorting very small samples

Hi Simon,
One strategy for sorting very small numbers of cells, in the hundred to
tens of hundreds range is the use of a "carrier sample" containing cells
with characteristics similar to those of the cells of interest yet
spectrally tagged as a separate population (normally with something like
DRAQ5 these days). This allows you to set the instrument up correctly
and yet avoid selection of the carrier cells. Then the critical step is
to run at event rates which dictate that coincidence occurrences are
very low. If you have a super stable setup, which for some cell
preparations is pretty routine, then the solution is to sort faster BUT
only single drop charges.
Another point worth mentioning is that double or triple labeling with
multiple fluorochromes to the same epitope to shift the population of
infrequent cell of the "diagonal" of autofluorescence in multiple
dimensions will also help allow you to pick a small population out of
the carrier cells.
 We have used these approach many times over the years to sort very
small samples. 

As to the microfluidics, don't hold you breath. Lots of potential, but
based on my experience with microfluidic devices we make here it is 4 to
5 years until we see a practical microfluidic sorter which can work day
in day out....but I'll be happy to be proven wrong.
Hope this helps
Geoff
--
Geoffrey Osborne
Director of Flow Cytometry,
The Queensland Brain Institute /Australian Institute for Bioengineering
and Nanotechnology,
The University of Queensland,
St Lucia, QLD, 4072, Australia
Ph (61) 07 33466397
email g.osborne@uq.edu.au
Please consider the environment before you print anything!

-----Original Message-----
From: SIMON MONARD [mailto:smonard@staffmail.ed.ac.uk] 
Sent: Wednesday, 9 July 2008 6:33 PM
To: cyto-inbox
Subject: Sorting very small samples

Greetings all.

We would be interested in an instrument that is able to sort cells  
from very small samples, from a few hundred to a few tens of thousands	
of cells. Speed is not an issue. Are any such instruments commercially	
available? Does anyone have one we can try? I have seen a few talks  
over the years about microfluidics and on chip sorting but have never  
seen an instrument Any suggestions?

Simon Monard
FACS Facility Manager
Institute for Stem Cell Research
University of Edinburgh
Roger Land Building
West Mains Road
Edinburgh
EH9 3JQ

Tel. Lab 0131 6505876
Tel Office 0131 6517265

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