 |
 |
 |
 |
 |
Hydrodynamics aside, there could be a problem with a refractive index
mismatch of the core and sheath fluids that will affect the direction of
light scatter and fluorescence and consequently, instrument alignment. (I
was reminded of this last week while kayaking on the coast of Vancouver
Island, and watching the blurring effect of a freshwater stream run under
the incoming tide--refractive index mismatch.)
Dave Coder
dcoder@u.washington.edu
----------
> From: Ray Hicks <rh208@cus.cam.ac.uk>
> To: Cytometry Mailing List <cytometry@flowcyt.cyto.purdue.edu>
> Cc: Cytometry Mailing List <cytometry@flowcyt.cyto.purdue.edu>
> Subject: Re: Viscosity Effects on FCM Analysis
> Date: Tuesday, June 17, 1997 3:15 AM
>
>
> Matt,
>
> Freyer-JP; Fillak-D; Jett-JH studied the effects of viscosity in a way in
> Cytometry. 1989 Nov; 10(6): 803-6, they used xanthan gum to slow the
> settling of cells prior to passing them through a cytometer. Xanthan is
> thixotropic or pseudoplastic, so although it's thick at rest, it flows
> easily under stress. How does your viscous medium behave?
>
> Another problem that might occur before you reach the point that your
> suspension won't go through the nozzle is that there may not be enough
> stress from the sheath to bring about hydrodynamic focusing or stretching
> of the core to produce the spatially constrained single file of cells
that
> we all know and love, you might get around this by upping the sheath
> pressure (you might need to increase sheath viscosity to prevent
> turbulence).
>
> On that last point, has anyone studied the effects of sheath viscosity
on
> core stability (and sample cv's) at high flow rates?
>
>
> Ray
>
>
> ISSN: 0196-4763At 8:17 am -0400 16/6/97, Matthew J Shaw wrote:
> > All,
> >
> > Does anyone have a good feel for the effects of higher viscosity
> > fluids being analyzed via flow cytometric means? For example, the
> > viscosity of water is 1 centipoise, and I assume that cells that
are
> > within water can be reliably analyzed. I believe that the
viscosity
> > of blood is perhaps 3 centipoise; again, I assume that cells within
> > this matrix can be reliably analyzed. However, if the matrix is
say
> > 10 centipoise, there may be a problem with forcing the matrix
through
> > the FCM nozzle. Maybe a problem doesn't exist until the matrix is
100
> > centipoise? Has anyone done a study like this on any flow
cytometer,
> > or have a good feel for this effect? What is the upper viscosity
> > limit before any problems may occur? (I realize that one could
dilute
> > the sample with a low-viscosity liquid until the desired viscosity
is
> > reached - I'd rather not have to do that!) I would appreciate any
help
> > on this matter.
> >
> > Matt Shaw
>
>
> Ray Hicks
> ________________________________________________________________________
> |University of Cambridge |Tel 01223 330149 |
> |Department of Medicine |Fax 01223 336846 |
> |Level 5, Addenbrookes Hospital |e-mail <rh208@cus.cam.ac.uk> |
> |Hills Road Cambridge |Web http://facsmac.med.cam.ac.uk |
> |CB2 |ftp server ftp://131.111.80.78 |
> |UK | |
> |_________________________________|_____________________________________|
>
|
|
|
|
|
|
CD-ROM Vol 3 was produced by Monica M. Shively and other staff at the
Purdue University Cytometry Laboratories and distributed free of charge
as an educational service to the cytometry community.
If you have any comments please direct them to
Dr. J. Paul Robinson, Professor & Director,
PUCL, Purdue University, West Lafayette, IN 47907.
Phone: (765)-494-0757;
FAX(765) 494-0517;
Web