AFDye 680 (Alexa Fluor ® 680 equivalent) is a bright and photostable near-IR dye that is spectrally identical to Alexa Fluor® 680 and IRDye® 680RD. AFDye 680 is often used for small animal imaging applications in the 700 nm wavelength and provides excellent clearance profiles in animals. Flow cytometry is another common application for this dye. AFDye 680 ideally suited for the 633 nm laser line. This near-IR fluorescent dye is water soluble and pH-insensitive from pH 4 to pH 10. AFDye 680 molecules can be attached to proteins at high molar ratios without significant self-quenching, leading to brighter conjugates and more sensitive detection. The long wavelength emission allows for detection in complex samples with auto-fluorescent background signals.
AFDye 680 is a carbonyl reactive building block used to modify carboxylic groups in the presence of activators (e.g. EDC, or DCC) or activated esters (e.g. NHS esters) through a stable amide bond. It also can be employed as a polar tracer, a reactive dye for labeling proteins via a carboxylic acid moiety, and amine donor for enzymatic transamination labeling.