CF™ Dyes

Watch the video for a brief introduction to CF™ dyes:

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.

New rhodamine chemistry

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.

Super-resolution microscopy

Recent publications comparing synthetic dyes for super-resolution imaging have shown CF™ dyes give the best performance for multiple methods. The superior brightness, photostability, and photochemical switching properties of certain CF™ dyes are ideal for 3-D SIM, 3-D STORM, and other super-resolution and single-molecule imaging approaches.

See publications for CF™ dyes in super-resolution microscopy

Unrivaled near-IR dyes

Near-IR dyes are larger in size than dyes in the visible range, resulting in low dye solubility, dye aggregation and poor fluorescence quantum yield. To overcome these problems, many near-IR dyes, such as the near-IR Alexa Fluor® dyes, DyLight® dyes and IRDyes®, are engineered to have negatively charged sulfonate groups. While sulfonation improves dye solubility and fluorescence quantum yield to some degree, it creates another serious problem: non-specific binding of the bioconjugates prepared from the dyes caused by the highly negatively charged dyes.

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. Our near-IR CF™ dyes 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.

Download a list of CF Dye References for all applications