CF™660C and CF™660R are two spectrally similar fluorescent dyes that emit fluorescence at about 685 nm in the borderline spectral region between far-red and near-IR (Figure 1). Although their absorption maxima are at around 660 nm, both dyes can be sufficiently excited by the 633 or 635 nm laser. When combined with other CF™ dyes of shorter wavelengths, CF™660C or CF™660R can serve as a useful long wavelength dye in multi-color detection applications. The two dyes are spectrally similar to Alexa Fluor® 660 but are far superior to the latter in performance.
Like Alexa Fluor® 660, CF™660C is a cyanine-based dye. However, when conjugated to protein, CF™660C is several fold brighter and significantly more photostable than Alexa Fluor® 660 (Figures 2 and 3). CF™660R is a rhodamine-based dye. Like rhodamine dyes in general, CF™660R is exceptionally photostable, compared to both Alexa Fluor® 660 and CF™660C (Figure 2). CF™660R is also much brighter than Alexa Fluor® 660, though not as bright as CF™660C (Figure 2). The superior photostability and excellent brightness of CF™660R make the dye an ideal choice for confocal microscopy and other demanding applications.
A full selection of reactive dyes, secondary antibodies, antibody labeling kits, and other bioconjugates including phalloidins, Annexin V and α-bungarotoxin are available for CF™ dyes.