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CF™405S Dye

CF™405S is a blue fluorescent dye with an absorption peak wavelength that nearly coincides with the 405 nm blue diode laser line (Figure 1). In addition, the emission peak wavelength of the dye well centers within the blue detection window of BD flow cytometers. As a result, flow cytometry analysis using CF™405S dye results in much brighter signal than that using Alexa Fluor® 405 (Figure 2). 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.

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CF™405S conjugates, labeling kits, and reactive dyes


Technical Summary

  • Abs/Em Maxima: 404/431 nm
  • Extinction coefficient: 33,000
  • Molecular weight: 1,169
  • Flow cytometry laser line: 405 nm
  • Microscopy laser line: 405 nm
  • Direct replacement for: Alexa Fluor® 405, Cascade Blue® dye, DyLight™ 405


  • Much brighter than Alexa Fluor® 405 due to better compatibility with both excitation and emission windows on common instruments
  • Highly water-soluble
  • pH-insensitive
Figure 1. Absorption and emission spectra of CF405S goat anti-mouse conjugate in PBS.
Figure 2. Intracellular staining of Jurkat cells was performed with mouse anti-CD3 or isotype control followed by goat anti-mouse conjugated to Alexa Fluor 405 (AF405) or CF405S with varying degrees of labeling (DOL, or dye molecules per antibody molecule). Fluorescence was analysed on a BD LSRII flow cytometer with 405 nm excitation and 450/50 nm emission filter. Bars represent the fluorescence of the geometric means of the cell populations.

Figure 3. HeLa cells stained with mouse anti-Golgin 97 and rabbit anti-COX IV followed by goat anti-mouse CF405S (Golgi, blue), goat anti-rabbit CF488A (mitochondria, green) and CF555 phalloidin (F-actin, red).