Polarization of Fluorescence Signals

From: Claudio Vallan (claudio.vallan@dkf7.unibe.ch)
Date: Fri Jan 18 2002 - 07:18:27 EST


Hello Cytometrists,

I was reading the Article "Polarization of Scatter and Fluorescencs Signals
in Flow Cytometry" (C.L Asbury, J. L. Uy and G. van den Engh: Cytometry 40/
2 p88-101) Amongst other in the paper they discribe why two particles that
emit the exactly same amount of fluorescence, but with different degrees of
anisotropy will not emit with the same intensity towards the detector.

I must admit that I did not understand every detail but I thought I more
ore less understood what they were talking about. Except for this statement
in the discussion:

" Althought one migth expect otherwise, this artifact [different intensity
measured from two particles with different anisotropy and same
fluorescence] cannot be avoided by using a circularly polarized laser or a
light beam from an unpolarized lamp. Whereas using a circualrly or randomly
polarized excitation beam will reduce the degree of fluorescence
anisotropy, it will not completely eliminate it."

Unfortunately here they stop with their explanations and thought I tried to
find out by my own why this must be so (Gedankenexperiment :-) ), I seem to
be too stupid to suceed. So I thought maybe someone else in this list knows
and could enlight me.

Thanks in advance

Greetings

Claudio

===================================================
Claudio Vallan PhD                          Phone Lab:      031 / 632 88 76
FACS-LAB DKF                               Phone Office:  031 / 632 99 68
University of Bern                         E-Mail:  vallan@dkf7.unibe.ch
c/o Institute of Pathology
Murtenstrasse 31                          Insel hosptial area only:
3010 Bern                                     Beeper:           181 67 59
Switzerland
===================================================



This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:59:21 EST