Alexa Fluor dyes

The number of new NIR fluorophores that can be used in biological systems has grown substantially in recent years as a consequence of extensive research efforts to improve the properties of available dyes. A brief overview of the various types of long-wavelength (above 600 nm) fluorophores including phycobiliproteins, BODIPY, and Alexa Fluor dyes (Life Technologies), Cy dyes (GE Healthcare),... 

The excitation and emission maxima of Alexa Fluor 647, 680, and 750 (the numbers indicate approximate absorption maxima in nanometers), and the molar absorptivities are in the same range as those for Cy5, Cy5.5, and Cy7, but Alexa Fluor dyes are reported to have major advantages in terms of their photostability,... 

Dramatic advances in modem fluorophore technology have been achieved with the introduction of Alexa Fluor dyes by Molecular Probes (Alexa Fluor is a registered trademark of Molecular Probes). Alexa Fluor dyes are available in a broad range of fluorescence excitation and emission wavelength maxima, ranging from the ultraviolet and deep blue to the near-infrared regions. Because of the large... 

Berlier JE et al (2003) Quantitative comparison of long-wavelength Alexa Fluor dyes to Cy dyes fluorescence of the dyes and their bioconjugates. J Histochem Cytochem 51 1699-1712... 

Direct labeling of a biomolecule involves the introduction of a covalently linked fluorophore in the nucleic acid sequence or in the amino acid sequence of a protein or antibody. Fluorescein, rhodamine derivatives, the Alexa, and BODIPY dyes (Molecular Probes [92]) as well as the cyanine dyes (Amersham Biosciences [134]) are widely used labels. These probe families show different absorption and emission wavelengths and span the whole visible spectrum (e.g., Alexa Fluor dyes show UV excitation at 350 nm to far red excitation at 633 nm). Furthermore, for differential expression analysis, probe families with similar chemical structures but different spectroscopic properties are desirable, for example the cyanine dyes Cy3 and Cy5 (excitation at 548 and 646 nm, respectively). The design of fluorescent labels is still an active area of research, and various new dyes have been reported that differ in terms of decay times, wavelength, conjugatibility, and quantum yields before and after conjugation [135]. New ruthenium markers have been reported as well [136]. 

Ibey BL, Cote GL, Yadavalli V, Gant VA, Newmyer K, Pishko MV. Analysis of Longer Wavelength Alexa Fluor Dyes for Use in a Minimally Invasive Glucose Sensor, Institute of Electrical and Electronics Engineers Inc., Cancun, Mexico, 2003, p. 3446. 

Abbreviations TMR (tetramethyirhodamine), Ci2 (chymotrypsin inhibitor 2), Cyx(cyanine dye, AK (adenosine kinase), AFxxir(Alexa Fluor dye xxx), CspTM (coid-shock protein from Thermotoga maritima), R6G (rhodamine 6G),TR (texas ted). Flu (fluorescein), bp (base pair). 

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