Re: DIOC6 Transmembrane
Howard Shapiro (hms@shapirolab.com)
Sat, 3 Feb 1996 22:03:25 -0500
The emission peak of DiOCn(3) is at around 504 nm; there is a tail going
relatively far into the red, and, at high concentrations (and with external
concentrations of 50 nm, you can get internal concentrations higher than 100
um, which qualifies as high), there is a noticeable red shift, although not
as much of one as is observed with JC-1. I thought of using the 575/525
emission ratio as a ratiometric membrane potential indicator, but it doesn't
work very well (neither, by the way, does ratiometry with JC-1). If, for
example, you try to use DiOC6(3) with a PE antibody to do "membrane
potential" and/or efflux pump measurements in antigenically defined cell
subpopulations, the cyanine dye fluorescence will clobber your PE
fluorescence. However, you can play this game by using FITC-antibodies and
substituting DiIC1(3) (or another DiICn(3)) as the membrane potential/efflux
indicator. Hope this helps.
--Howard
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