DyLight Fluor

	Color	mass (g/mol)	Absorb (nm)	Emit (nm)	ε (M-1cm-1)
DyLight 488	green	1011	493	518	70,000
DyLight 549	yellow	982	550	568	150,000
DyLight 649	red	1008	646	674	250,000
DyLight 680	near-IR	950	682	715	140,000
DyLight 800	near-IR	1050	770	794	270,000

The DyLight Fluor family of fluorescent dyes is produced by Thermo Fisher Scientific. DyLight Dyes are typically used in biotechnology and research applications as biomolecule, cell and tissue labels for fluorescence microscopy, cell biology or molecular biology.

The excitation and emission spectra of the DyLight Fluor series covers much of the visible spectrum and extends into the infrared region, allowing detection using most fluorescence microscopes, as well as infrared imaging systems.

DyLight Fluors are synthesized through sulfonate addition to coumarin, rhodamine, xanthene (such as fluorescein), and cyanine dyes. Sulfonation makes DyLight Dyes negatively charged and hydrophilic. DyLight Fluors are commercially available as reactive succinimidyl-esters for labeling proteins through lysine residues, and as maleimide derivatives for labeling proteins through cysteine residues.

Historically, fluors such as fluorescein, rhodamine, Cy3 and Cy5 have been used in a wide variety of applications. These dyes have major limitations for use in microscopy and other applications that require exposure to a laser light source, because they photobleach quickly. DyLight Fluors have comparable excitation and emission spectra and are generally more photostable, brighter, and less pH-sensitive.

The Alexa Fluor dyes are a similar line of fluorescent dyes from Invitrogen that offer comparable alternatives to the DyLight Fluors.