FACS query

Derek Davies derek_davies at postmaster.co.uk
Mon Jul 6 01:48:56 EST 1998

In article <6nhvcd$ajb$1 at nnrp1.dejanews.com>, darren at indy.bio.uts.edu.au wrote:

> I have a colleague who wants to analyse algal cells using our FACS machine.
> Basically, he wants to excite the algal cells at one wavelength and detect at
> another, which is as I understand it how FACS works- it excites at 488nm and
> detects up to 3 (ranges of) wavelengths . However, he wants to vary the
> excitation wavelength to eg 640nm and then detect flourescence at say
> 670-700nm. Is this plausible/possible? I don't think it is on our machine (We
> have a BD single laser FACScan) but maybe on a different model?
> Thanks, Darren Jones

Hi Darren,

You are right, it isn't possible on a single laser FACScan. To excite at
around 640 
you will need a red laser. The dual laser FACS Calibur comes with a 635nm red
diode laser which would do the job. The alternative is to fine a sorter
equipped with a Helium-Neon laser (again emitting at 635nm). The collection
filters of both machines can be set to the specific wavelength required.


Derek Davies, FACS Laboratory, ICRF, London.

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