Fluorescent measurement of nano scale particles.
max.warncke at uniklinik-freiburg.de
Mon Jun 11 06:05:21 EDT 2007
Can I use flow cytometry to analyze the coupling efficiency of a
fluorescent dye to a 200nm dextran coated iron particle?
I coupled AlxFluor 647 hydrazide to a carboxyl containing bead by EDC
(carbodiimide). After coupling I get a very strong signal in the APC
channel, but I was not able to trigger the bead population. I tried use
side scatter or fluorescence instead of forward scatter as trigger, but
without success. Does anyone has a protocol for measuring fluorescent
nano particles or a idea which method could be suitable for this?
I also coupled an antibody to the fluorescent beads, but then I had the
same problems. If I incubate cells with the fluorescent bead I cannot
completely separate the beads from the cells by washing. The beads which
are still in the solution are producing a very strong background signal
and I am not able to trigger only on the cells.
(I have attached an example: two cell populations. the B220 positive
population has the specific receptor, the B220 negative does not.
incubating only with a fluorescent coupled antibody doesn't produce a
I would be very happy about any suggestions.
Max Warncke, Ph.D. (max.warncke at uniklinik-freiburg)
Department of Hematology & Oncology
University Freiburg Medical Center
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