Re: dye lasers
Howard Shapiro (hms@shapirolab.com)
Mon, 26 Feb 1996 17:58:48 -0500 (EST)
The APC-Cy7 tandem, while not yet commercially available, is excited nearly
optimally by 633 nm He-Ne (or 635 nm diode) lasers. Mike Loken et al showed
years ago that FACStar class (and presumably FACS VAntage) sorters don't
need more than 50 mW excitation for APC, and 25 was almost as good; these
power levels are readily available from He-Ne's, and 15 mW diodes are now on
the market (B-D has put one in the FACSCalibur). The APC/APC-Cy7 combo is
probably as effective as Texas Red/APC when one uses the same dye laser to
excite TR optimally and APC suboptimally.
My air-cooled argon laser puts out over 125 mW at 488 or 515 nm, which was
about as much as I'd use out of a water-cooled laser years ago. You
shouldn't need much more than that with any of B-D's or Coulter's machines,
and I'm not sure that you'd need more for a Cytomation system doing
immunofluorescence. The major reason for using humungous power levels for
high speed chromosome sorting has to do with saturating the dye, which you
almost certainly don't want to do with phycobiliproteins or other
immunofluorescent tags.
--Howard