J. Membrane Biol. 27, 317-334 (1976)
9 by Springer-Verlag New York Inc. 1976
Optical Probes of Membrane Potential Alan Waggoner Department of Chemistry, Amherst College, Amherst, Massachusetts 01002 Received 12 February 1976
Summary. There are two basically different mechanisms for the fluorescence and absorption changes of merocyanine, cyanine and oxonol dyes. The permeant dyes (cyanine and oxonol dyes, with delocalized charges) work by a potential-dependent accumulation mechanism. These dyes show large (up to 80%) fluorescence and absorption changes with suspensions of cells, and the changes are complete in seconds. The impermeant dyes (merocyanine dyes, with localized charges) and the permeant dyes also show optical changes that take place in fractions of milliseconds. The rapid optical changes are relatively small (_-
9 by Springer-Verlag New York Inc. 1976
Optical Probes of Membrane Potential Alan Waggoner Department of Chemistry, Amherst College, Amherst, Massachusetts 01002 Received 12 February 1976
Summary. There are two basically different mechanisms for the fluorescence and absorption changes of merocyanine, cyanine and oxonol dyes. The permeant dyes (cyanine and oxonol dyes, with delocalized charges) work by a potential-dependent accumulation mechanism. These dyes show large (up to 80%) fluorescence and absorption changes with suspensions of cells, and the changes are complete in seconds. The impermeant dyes (merocyanine dyes, with localized charges) and the permeant dyes also show optical changes that take place in fractions of milliseconds. The rapid optical changes are relatively small (_-
