Alexa Fluor dyes are superior to Cy dyes for antibody labeling by having combined advantages in brightness, photostability, specificity and novel features ideal for in vivo imaging.
Alexa Fluor 488 is exceptionally bright and its fluorescence is insensitive to pH. Moreover, Alexa Fluor 488 is far more photostable than FITC or fluorescein. Alexa Fluor 488 is a better choice for instruments that use 470 nm blue light excitation and/or a fluorescence detection window that centers at a relatively shorter wavelength. For example, if your detection window is from 510 to 540 nm or centers at an even shorter wavelength, Alexa Fluor 488 would be a superior choice. The shorter wavelength of Alexa Fluor 488 offers the advantage of less fluorescence “spill over” in the red channel in multi-color detection applications.
Antoher advantage of Alexa Fluor 488 labeled antibodies is their unrivaled specificity. These antibodies offer results in better signal to noise ratio in demanding applications such as tissue staining, cell staining.