Diode Lasers/Cell Volume/Hybrids
Howard Shapiro (HPANDA@HARVARDA.HARVARD.EDU)
Fri, 16 Sep 94 14:33:16 EST
Regarding three questions posed recently:
Visible diode lasers with >10 mW power at 635-650 nm have only recently
become available. Spectra Diode Labs makes a 15 mW, 635 nm diode; Philips
makes a 100 mW, 650 nm diode. Laser systems incorporating these diodes,
regulated power supplies, and focusing optics are available from Power
Technology, Inc., in Mabelvale, AR (Phone (501)568-1995, FAX 568-1994);
a 5 mW 635 nm system is about $350-$500, the 15 mW unit is $600-$900,
and the 100 mW system is about $3,000.
Measuring cell volume with dyes binding to membranes: if cells were
spherical, volume could be computed from surface area, but they aren't.
Concentration of material in cells can probably be estimated adequately
for most purposes by assuming forward scatter amplitude is proportional
to the square of the radius, which would make volume proportional to
the 3/2 power of scatter amplitude.
Identifying cell hybrids: The older references are Schaap et al, Exptl
Cell Res 140:299, 1982, and Jongkind and Verkerk, Cytometry 5:182, 1984;
more recently, Tertov et al (J Immunol Methods 118:139, 1989) described
the use of energy transfer between tracking dyes to identify hybrids.
The diode laser stuff is so new it isn't in the 3rd Edition of P. F. C.,
which should be available at the ISAC meeting. Hope to see y'all there.
--Howard
CD ROM Vol 2 was produced by 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:(317) 494-0757; FAX (317) 494-0517; Web http://www.cyto.purdue.edu
EMAIL robinson@flowcyt.cyto.purdue.edu
