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CF™640R Dye

CF™640R is a rhodamine-based far-red fluorescent dye with excitation and emission maxima very similar to those of Cy®5 and Alexa Fluor® 647 (Figure 1). CF™640R is much brighter than Cy®5 and at least as bright as Alexa Fluor® 647 (Figure 2). A major advantage of CF™640R over Cy®5 and Alexa Fluor® 647 is its exceptional photostability. Cy®5 and Alexa Fluor® 647 are cyanine-based dyes and, like other cyanine dyes in general, have intrinsically poor photostability.

CF™640R is also superior to ATTO™ 647N, another spectrally similar dye frequently used in single-molecule imaging. As shown in Figures 2 and 3, CF™640R is significantly brighter and more photostable than the ATTO™ dye. The combination of excellent brightness and photostability makes CF™640R ideal for confocal microscopy, single- molecule imaging and other demanding applications based on fluorescence detection.

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.

View products associated with this technology…

CF™640R conjugates, labeling kits, and reactive dyes

Technical Summary

  • Abs/Em Maxima: 642/662 nm
  • Extinction coefficient: 105,000
  • Molecular weight: ~832
  • Flow cytometry laser line: 633, 635 or 640 nm
  • Microscopy laser line: 633, 635 or 640 nm
  • Direct replacement for: Cy®5, Alexa Fluor® 647 and ATTO™ 647N

Advantages

  • Has the best photostability among dyes with Cy®5-like spectra
  • Yields highly fluorescent protein conjugates
  • Very water-soluble and pH-insensitive
Figure 1. Absorption and emission spectra of CF™640R and Cy®5 conjugated to goat anti-mouse IgG in PBS.
Figure 1. Absorption and emission spectra of CF™640R and Cy®5 conjugated to goat anti-mouse IgG in PBS.
Figure 2. Jurkat cells were stained with intracellular CD3 followed by goat anti-mouse IgG conjugates. Background staining was determined by secondary antibody staining alone. Fluorescence was analyzed on a BD FACS Calibur in the FL4 channel. The bars represent the relative fluorescence of the geometric means of the population of cells.
Figure 2. Jurkat cells were stained with intracellular CD3 followed by goat anti-mouse IgG conjugates. Background staining was determined by secondary antibody staining alone. Fluorescence was analyzed on a BD FACS Calibur in the FL4 channel. The bars represent the relative fluorescence of the geometric means of the population of cells.
Figure 3. Photostability comparison between CF™640R and ATTO™647N, a far-red dye frequently used in single-molecule imaging. Dye solutions at 0.5 mM in PBS were continuously exposed using a Cy®5 filter set on a mercury arc lamp microscope. Images were captured every 15 seconds, and mean fluorescence intensity of each image was calculated using Image Pro Express software.
Figure 3. Photostability comparison between CF™640R and ATTO™647N, a far-red dye frequently used in single-molecule imaging. Dye solutions at 0.5 mM in PBS were continuously exposed using a Cy®5 filter set on a mercury arc lamp microscope. Images were captured every 15 seconds, and mean fluorescence intensity of each image was calculated using Image Pro Express software.