CF™647 is a cyanine-based far-red fluorescent dye spectrally similar to Cy®5 and Alexa Fluor® 647 (Figure 1). Compared with the other dyes, CF™647 has good fluorescence brightness (Figures 2 and 3A). However, the most attractive feature of CF™647 is its superior signal-to-noise ratio for its antibody conjugates in immunostaining (Figure 3B). Alexa Fluor® 647 bears multiple negative charges, which improve the brightness of the dye but also significantly alter the isoelectric point of antibody conjugates, resulting in lowered specificity of the conjugates.
To overcome the problem, a polymer blocking agent, such as Image-it™, is recommended to pre-treat the sample prior to the staining. CF™647, on the other hand, is minimally charged. As a result, antibody conjugates prepared from the dye have excellent specificity.
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.