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We offer a wide range of antibodies conjugated to all of the most commonly used fluorophores. In addition to FITC, PE, and APC, we also offer Alexa Fluor and DyLight conjugates in an array of colors, both with outstanding spectral properties.
If we don’t have the labeled version you are seeking, we offer easy-to-use LYNX Rapid Conjugation Kits® for many popular dyes and tandem conjugates and Readilink Antibody Conjugation Kits for flow cytometry optimized fluorophores.
Fluorophore | Fluorescence color | Maximum excitation (nm) | Maximum emission (nm) |
Relative
brightness
|
Spectrally similar dyes |
---|---|---|---|---|---|
DyLight 405 | 400 | 420 | 3 | Alexa Fluor 405, Cascade Blue | |
Alexa Fluor 405 | 401 | 421 | 3 | ||
Pacific Blue | 410 | 455 | 1 | ||
DyLight 488 | 493 | 518 | 4 | Alexa Fluor 488, FITC | |
Alexa Fluor 488 | 495 | 519 | 3 | Cy2, DyLight 488, FITC | |
FITC | 490 | 525 | 3 | Alexa Fluor 488, Cy2, DyLight 488 | |
DyLight 550 | 562 | 576 | 4 | Alexa Fluor 546, Alexa Fluor 555, Cy3, TRITC | |
PE | 496, 546 | 578 | 5 | ||
hFab™ Rhodamine* | 530 | 580 | 3 | ||
Texas Red | 596 | 615 | 2 | ||
APC | 650 | 661 | 4 | Alexa Fluor 647, Cy5 | |
Alexa Fluor 647 | 650 | 665 | 4 | APC, Cy5, DyLight 650 | |
Cy5 | 649 | 670 | 3 | ||
DyLight 650 | 654 | 673 | 4 | Alexa Fluor 647, Cy5 | |
PerCP | 490 | 675 | 2 | ||
StarBright™ Blue 700* | 470 | 700 | 5 | ||
DyLight 680 | 692 | 712 | 4 | Alexa Fluor 680, Cy5.5 | |
Alexa Fluor 700 | Infrared | 702 | 723 | 2 | |
DyLight 755 | Infrared | 752 | 778 | 4 | Alexa Fluor 750 |
DyLight 800* | Infrared | 777 | 794 | 4 | IR Dye 800 |
* Western blot tested
Abbreviations: APC; allophycocyanin, FITC; fluorescein isothiocyanate, PE; phycoerythrin (Note. phycoerythrin (PE) is the same as R-phycoerythrin (RPE)), PerCP; peridinin-chlorophyll-protein complex.
When designing panels of eight or more colors, tandem dyes, such as APC-Cy7, have to be included. This is due to both laser excitation and single fluorophores limitations, which make it necessary for a single laser to excite the maximum number of fluorophores possible.
Tandem dyes, as the name implies, consist of two different covalently attached fluorophores (a donor and an acceptor molecule). With regards to spectral properties, the tandem dye has the excitation characteristics of the donor fluorophores and the emission characteristics of the acceptor molecule. These properties are due to Förster resonance energy transfer (FRET; also known as Fluorescence resonance energy transfer); a process in which energy is passed on from an excited donor to a nearby acceptor molecule, which then emits a photon of light.
For tandem dyes the following guidelines should be followed:
Fluorophore | Fluorescence color | Maximum excitation (nm) | Maximum emission (nm) |
Relative
brightness
|
Spectrally similar dyes |
---|---|---|---|---|---|
PE-Alexa Fluor 647 | 496, 546 | 667 | 4 | ||
PE-Cy5 | 496, 546 | 667 | 5 | ||
PE-Cy5.5 | 496, 546 | 695 | 4 | ||
PE-Alexa Fluor 700 | Infrared | 496, 546 | 723 | 2 | PE-Cy5, PerCP |
PE-Alexa Fluor 750 | Infrared | 496, 546 | 779 | 4 | PE-Cy7 |
APC-Alexa Fluor 750 | Infrared | 650 | 779 | 4 | APC-Cy7, DyLight 750 |
PE-Cy7 | Infrared | 496, 546 | 785 | 4 | PE-Alexa Fluor 750 |
APC-Cy7 | Infrared | 650 | 785 | 2 |
Abbreviations: APC; allophycocyanin, FITC; fluorescein isothiocyanate, PE; phycoerythrin (Note. phycoerythrin (PE) is the same as R-phycoerythrin (RPE)), PerCP; peridinin-chlorophyll-protein complex.
Although some fluorophores may have similar excitation and emission wavelengths, their relative brightness may be different. Fluorophore brightness depends on how many photons a fluorophore emits when being excited by a laser, as well as the conversion rate of those photons when they hit the detectors and are converted into electrons. The relative brightness can be an important factor in flow cytometry to obtain good signal resolution. If an antigen is highly abundant, most fluorophores can be used, however low abundance antigens and rare cell populations will require bright fluorophores to achieve sufficient separation from the negative population. When building larger panels, good separation will improve the analysis of your data and may allow you some leeway in your fluorophore choices. The graphs below show how fluorophore brightness can affect the appearance of flow cytometry data.
Laser line | Maximum excitation (nm) | Maximum emission (nm) | Filter | Relative brightness | |
---|---|---|---|---|---|
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405 | 410 | 455 | 460/22 | 1 |
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640 | 702 | 723 | 720/60 | 2 |
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488 | 490 | 525 | 525/35 | 3 |
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640 | 650 | 665 | 670/30 | 4 |
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561 | 546 | 578 | 577/15 | 5 |
Fig. 1. Fluorophore relative brightness. Examples of staining showing the relative brightness of common fluorophores on the same cell population. Data collected on the ZE5™ Cell Analyzer.
Many factors will affect the appearance of data. This can be the flow cytometer, filters and laser used to excite the fluorophore, the laser power and instrument settings as well as the type of plot chosen. Other examples include the sample used, antibody clone, the F:P ratio and staining protocol. Finally, remember that each fluorophore will influence another in a multicolor panel so compensation and fluorescence spread should be considered when choosing a fluorophore.
For more information about fluorophores and immunophenotyping, refer to our flow cytometry resources.
Click on the links below to find more in-depth information on each topic and view our popular flow cytometry basics guide