Widely used green fluorescent dye for cell staining.
- Standard green fluorophore
Fluorescein is a widely used green fluorescent fluorophore for use in cell labeling studies. Fluorescein is a fluorophore commonly used in microscopy, as a type of dye laser as the gain medium, as a stain in forensics and serology to detect latent blood stains, and as a standard for many fluorescence based enzyme assays. Fluorescein has an absorption maximum at 494 nm and emission maximum of 521 nm (in water). Several major derivatives of fluorescein are fluorescein isothiocyanate (FITC) and 6-FAM phosphoramidite used in oligonucleotide labeling and sequencing. Fluorescein has an isosbestic point (a point with equal absorption at all pH values) of 460 nm. Fluorescein is also known as a color additive (D&C Yellow no. 7) with the more water soluble disodium salt form of fluorescein is known as uranine (D&C Yellow no. 8).