IRDye infrared dyes from LI-COR Biosciences are available for researchers developing applications using near-infrared (NIR) fluorescence. These unique dyes are used in a variety of NIR imaging applications including Western blotting, plate-based assays, protein arrays, tissue section imaging, and molecular activity measurements. Standard NHS ester chemistry is used to produce custom probes labeled with LI-COR IRDye infrared dyes. The NHS ester reactive group provides the functionality for labeling primary and secondary amines, such as lysine residues in proteins.