Exceptionally bright and photostable fluorescent CFTMdye conjugates
Secondary antibodies and bioconjugates for immunofluorescence staining
Near-infrared dye conjugates for Western blotting and in vivo imaging
Reactive dyes and protein labeling kits
Mix-n-StainTM Antibody Labeling Kits for rapid antibody labeling
VivoBriteTM Rapid Antibody Labeling kits for near-infrared small animal imaging
Download the CF™ Dye Quick Reference Table Download our CF™ Dye Selection Guide CF™ Dye References
Download the CF™ Dye Quick Reference Table, CF™ Dye Selection Guide, or click on a CF™ dye on the left sidebar for more information on an individual dye.
CF™ dyes are a series of highly water-soluble fluorescent dyes spanning the visible and near-infrared (NIR) spectrum for labeling biomolecules, especially proteins and nucleic acids. Developed by scientists at Biotium using new breakthrough chemistries, CF™ dyes rival or exceed the quality of other commercial dyes, such as Alexa Fluor® dyes, due to the following novel features.
Rhodamine dyes are known for their excellent photostability and good fluorescence quantum yield; consequently several of the Alexa Fluor® dyes bear the rhodamine core structure.
Unfortunately, traditional rhodamine chemistry makes it difficult to extend the fluorescence wavelength to the far-red region and even more challenging in the near-IR region, especially for water-soluble dyes for bioconjugation. Recently, Biotium scientists discovered a new way to prepare novel rhodamine dyes of any fluorescence color from green to near-IR.
The new chemistry is a key element in the development of many of our CF™ dyes, particularly our far-red CF™ dyes, which are not only bright and water-soluble but also extremely photostable.
Excellent labeling efficiency
Reactive dyes for bioconjugation are generally susceptible to hydrolysis, which can cause problems for shipping, handling and storage and result in lower labeling efficiency. Heavily sulfonated dyes, such as the Alexa Fluor® dyes, DyLight® dyes and IRDye® are particularly hygroscopic, worsening the hydrolysis problem.
For example, the percent of active Alexa Fluor® 488 succinimidyl ester (SE) could be well below 50% by the time of application (Alexa Fluor 488 microscale labeling kit product information sheet, Invitrogen). In contrast, all of Biotium’s amine-reactive CF™ dyes have a relatively stable form of SE, which is more resistant to hydrolysis than the SE in many of the Alexa Fluor dyes. Accordingly, CF™ dye SE products generally give consistently higher labeling efficiency, thus providing users a better value.
Mix-n-Stain™ antibody labeling technology
Biotium has developed a breakthrough antibody labeling technology with CF™ dyes — Mix-n-Stain™ antibody labeling kits. With this technology, you merely need to mix your antibody with the reaction buffer and CF™ dye provided in the kit, and in 30 minutes you will have an optimally labeled CF™ dye-antibody conjugate ready for immunostaining.
Mix-n-Stain™ provides unprecedented convenience for multicolor immunostaining, where pre-labeled primary antibodies may not be available while indirect staining via prelabeled fluorescent secondary antibodies may also be difficult due to cross-interaction among different antibodies.
Near-IR dyes are typically much larger in size than dyes in the visible range. The large size often results in serious problems of low dye solubility, dye aggregation and poor fluorescence quantum yield. To overcome the problems, many commercial near-IR dyes, such as the near-IR Alexa Fluor® dyes, DyLight® dyes and IRDyes®, are prepared by placing a number of negatively charged sulfonate group on the dyes. While sulfonation improves dye solubility and fluorescence quantum yield to some degree, it creates another even more serious problem: non-specific binding of the bioconjugates prepared from the dyes.
For example, conjugation to a highly negatively charged dye can dramatically alter an antibody’s isoelectric point (iP), which is essential for maintaining specific antibody-antigen interaction. With this insight, Biotium scientists devised a revolutionary new approach to near-IR dye design that results in superior physical properties of the dyes without introducing an excessive amount of negative charge.
Biotium’s near-IR CF™ dyes are based on the core structure of either cyanine dyes or rhodamine dyes. Those core structures are modified such that the intramolecular mobility of the dyes is restricted, which leads to higher quantum yield and better water solubility without adding excessive charge. As a result, near-IR CF™ dyes are much brighter and more photostable than any other near-IR dyes. Most importantly, antibodies labeled with near-IR CF dyes™ give far better signal-to-noise ratio in immunostaining compared with antibody conjugates prepared with other commercial near-IR dyes.
Multi-color flexibility
Biotium currently offers 20 CF™ dyes spanning the visible, far-red, and near-infrared spectra, with additional colors in development. The CF™ dye product line includes reactive dyes, secondary antibodies, streptavidin, phallodin and other conjugates, and antibody labeling kits.
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