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CF®660C & CF®660R

Superior alternatives to Alexa Fluor® 660

Far brighter & more photostable than Alexa Fluor®
CF®660C is compatible with multi-color STORM
CF®660R has unrivaled photostability

Figure 1. Normalized absorption and emission spectra for CF®660C (solid lines) and CF®660R (dashed lines) goat anti-mouse conjugates in PBS.

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®660C is also validated in multi-color super-resolution imaging by STORM (learn more about CF® dyes for super-resolution microscopy).

CF®660R is a rhodamine-based dye, and like rhodamine dyes in general, it is exceptionally photostable (Figure 3). CF®660R is also brighter than Alexa Fluor® 660 (Figure 2). The superior photostability and excellent brightness of CF®660R make the dye an ideal choice for confocal microscopy and other demanding applications.

Figure 2. CF®660C yields much brighter antibody conjugates than Alexa Fluor® 660. CF®660R also is brighter than Alexa Fluor® 660. Relative brightness of goat anti-mouse conjugates of the dyes as a function of degree of labeling (DOL, or dye molecules per antibody molecule).

CF®660C Technical Summary

  • Abs/Em maxima: 667/685 nm
  • Extinction coefficient: 200,000
  • Molecular weight: ~3112
  • Laser line: 633 or 635 nm
  • Direct replacement for: Alexa Fluor® 660, Allophycocyanin (APC)

CF™660R Technical Summary

  • Abs/Em maxima: 663/682 nm
  • Extinction coefficient: 100,000
  • Molecular weight: ~888
  • Laser line: 633 or 635 nm
  • Direct replacement for: Alexa Fluor® 660, Allophycocyanin (APC)

Figure 3. CF®660 is extremely photostable. CF®660C also is more photostable than Alexa Fluor® 660. HeLa cells were stained with mouse anti-tubulin and goat anti-mouse dye conjugates. Cells were continuously exposed to mercury arc lamp excitation through a Cy®5 filter set. Images were captured every 10 seconds for five minutes, and average fluorescence intensity was normalized to time 0.
Figure 4. Comparison of microtubule imaging using conventional wide-field microscopy with STORM using CF®660C conjugate. Images courtesy of Sam Kenny and Professor Ke Xu, College of Chemistry, University of California, Berkeley.

CF is a registered trademark of Biotium, Inc. Alexa Fluor is a registered trademark of Thermo Fisher Scientific.

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Lectins, proteins, nucleotides, toxins, and other probes conjugated to our bright & photostable CF® dyes and other labels.

Primary Antibodies

Growing collection of more than 1000 monoclonal antibodies validated in IHC and other applications. Available with bright and photostable CF® dyes, R-PE, APC, PerCP, HRP, AP, biotin, or purified. Affordable 100 uL trial sizes.

CF® Dye Labeled & Biotinylated Secondary Antibodies

Many host/target species and cross-absorption options, featuring a wide spectrum of our bright & photostable CF® dyes or biotin.

CF® Dye Single Label Conjugates for STORM

Secondary antibody conjugates of our STORM-compatible CF® dyes, with an average degree of labeling (DOL) of one, specifically designed for super-resolution imaging by STORM.

Mix-n-Stain™ Antibody Labeling Kits

Mix-n-Stain™ kits use revolutionary technology that dramatically simplifies antibody labeling and requires no purification. The labeling is covalent and stable. Available with your choice of 24 CF® dyes, biotin, FITC, fluorescent proteins, enzymes, or haptens.

CF® Dye Protein Labeling Kits

Everything you need to label and purify antibodies or other proteins. Choose from 19 bright & photostable CF® dyes or biotin.

Reactive CF® Dyes

Our bright, photostable, highly water soluble CF® dyes with a wide selection of colors and functional groups.

Additional conjugates or reactive dye forms may be added on request, contact to inquire.

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CF® Dyes

See our CF® Dye Quick Reference Table for a list of dyes and summary of their features. Our CF® Dye Selection Guide has more detailed information on each CF® dye, and ordering information for our various CF® dye product lines. You can download CF® dye normalized absorption and emission data in Excel format.

Category: Mix-n-Stain™ Antibody Labeling Kits, CF® Dyes

← FAQs
CF® initially was an abbreviation for Cyanine-based Fluorescent dyes. These were the first patented CF® dyes based on cyanine dye structures. Since then, our CF® dye patent portfolio has expanded to include four different fluorescent dye core structures that cover the fluorescence spectrum from UV to NIR.

Category: CF® Dyes

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The exact chemical structures of CF® dyes are currently confidential but will be fully disclosed at a later stage when pending patents become granted. In general terms, the structure of a CF® dye may be divided into two parts: a) dye core structure (i.e. the aromatic ring skeleton that defines the dye’s color or absorption/emission wavelengths), and b) core structure-modifying elements. At present, CF® dyes bear the core structures of coumarin, pyrene, rhodamine or cyanine dyes. Blue fluorescent CF® dyes are based on coumarin or pyrene dye core structure, while green to near-IR CF® dyes are based on either cyanine or rhodamine dye core structures. Core structure-modifying elements refer to various chemical attachments to the core structure and are a key aspect of the CF® dye invention that makes CF® dyes superior to other commercial dyes.

Category: CF® Dyes

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