Alexa Fluor

The Alexa Fluor family of fluorescent dyes is a series of dyes invented by Molecular Probes, now a part of Thermo Fisher Scientific, and sold under the Invitrogen brand name. Alexa Fluor dyes are frequently used as cell and tissue labels in fluorescence microscopy and cell biology. Alexa Fluor dyes can be conjugated directly to primary antibodies or to secondary antibodies to amplify signal and sensitivity or other biomolecules.

The excitation and emission spectra of the Alexa Fluor series cover the visible spectrum and extend into the infrared. The individual members of the family are numbered according roughly to their excitation maxima in nanometers.