Alexa Fluor is a series of fluorescent dyes developed by American Molecular Probes, which can be used in the labeling and localization of tissues, cells and biomolecules in biomedical research. Its excitation and emission spectra cover most of the visible and part of the infrared spectral region and are suitable for most fluorescence microscopes.
The Alexa series of dyes are named after Alex Haugland, son of Dick Haugland, one of the founders of Molecular Probes. Another fluorescent dye product of the company, Marina Blue, is named after its daughter Marina.
Each dye in this series is named mainly according to the maximum wavelength (nm) of its excitation light.
Molecular Probes was acquired in 2003 by Invitrogen, who worked to further expand the Alexa Fluor family by the addition of new dyes to fill gaps not covered in the emission spectrum. In 2008, Invitrogen and the Alexa Fluor product line became a part of the Life Technologies, after the Invitrogen merger with Applied Biosystems. In 2014, Life Technologies was acquired by Thermo Fisher Scientific, who revitalized the Invitrogen name and brand, bringing the Alexa Fluor product line back under it.
Product comparison
Alexa series dyes introduce sulfonate groups into coumarin, xanthene (such as fluorescein and rhodamine), cyanine and other dyes through chemical synthesis, making Alexa dyes negatively charged and hydrophilic, making Alexa possess Better optical stability, luminous intensity and pH adaptability. American Life Technologies has related patents after acquiring Molecular Probes.
A third-party organization has compared DNA staining with AlexaFluor647 and Cy5 (which have similar wavelengths) and found that Cy5 is brighter in color, but less optically stable than Alexa 647. Another study found that the dyeing brightness of Alexa dyes had better photostability (eg comparison of AlexaFluor488 with Dylight488 and Fluoprobes488.
| Colour† | Absorb (nm) |
Emit (nm) |
MM (g/mol) |
ε (cm−1M−1) |
Quantum Yield | |
|---|---|---|---|---|---|---|
| Alexa Fluor 350 | Blue | 346 | 442 | 410 | 19,000 | – |
| — 405 | Blue | 401 | 421 | 1028 | 35,000 | – |
| — 430 | Green | 434 | 541 | 702 | 15,000 | – |
| — Alexa Fluor 488 NHS ester | Green | 495 | 519 | 643 | 73,000 | 0.92 |
| — 500 | Green | 502 | 525 | 700 | 71,000 | – |
| — 514 | Green | 517 | 542 | 714 | 80,000 | – |
| — Alexa 532 | Yellow | 532 | 554 | 721 | 81,000 | 0.61 |
| — Alexa Fluor 546 | Yellow | 556 | 573 | 1079 | 112,000 | 0.79 |
| — Alexa Fluor 555 | Orange | 555 | 565 | ~1250 | 155,000 | 0.1 |
| — Alexa Fluor 568 | Orange | 578 | 603 | 792 | 88,000 | 0.69 |
| — 594 | Red | 590 | 617 | 820 | 92,000 | 0.66 |
| — 610 | Red | 612 | 628 | 1172 | 144,000 | – |
| — Alexa Fluor 633 | Far-red | 632 | 647 | ~1200 | 159,000 | – |
| — 635 | Far-red | 633 | 647 | – | 140,000 | – |
| — Alexa Fluor 647 nhs ester | Far-red | 650 | 665 | 1155.06 | 270,000 | 0.33 |
| — Alexa Fluor 660 | Near-IR | 663 | 690 | ~1100 | 132,000 | 0.37 |
| — Alexa Fluor 680 | Near-IR | 679 | 702 | ~1150 | 183,000 | 0.36 |
| — 700 | Near-IR | 702 | 723 | ~1400 | 205,000 | 0.25 |
| — 750 | Near-IR | 749 | 775 | ~1300 | 290,000 | 0.12 |
| — 790 | Near-IR | 782 | 805 | ~1750 | 260,000 | – |
| † = approximate colour of the emission spectrum ε = extinction coefficient |
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Alexa fluors equivalent fluorescent dye APDye
APDye Fluors is the equivalent fluorescent dye of alexa fluors developed by axispharm. APDye Fluors series fluorescent dyes are bright in color, optically stable, very good in light stability of dyeing brightness, and very competitive in price. It can be applied to the labeling and localization of tissues, cells and biomolecules in biomedical research. Its excitation and emission spectra cover most of the visible and part of the infrared spectral region and are suitable for most fluorescence microscopes.
APDye Fluors
APDye Fluor 350
APDye Fluor 405
APDye Fluor 430
APDye Fluor 488
APDye Fluor 532
APDye Fluor 546
APDye Fluor 555
APDye Fluor 568
APDye Fluor 594
APDye Fluor 633
APDye Fluor 647
APDye Fluor 660
APDye Fluor 680
APDye Fluor 800