XFD660 azide

• Ex/Em: 663/691 nm
• Extinction coefficient: 132,000 cm^-1M^-1
• Superior Fluorescence Performance: High quantum yield, exceptional photostability, and pH-independent fluorescence across pH 4–11.
• Reactive Group: Azide
• Click Chemistry Conjugation: Efficiently and rapidly labels terminal alkynes via CuAAC and copper-free SPAAC
• High Water-Solubility: Prevents aggregation and enhances signal clarity for advanced imaging and live-cell applications

XFD660, manufactured by AAT Bioquest, is a far-red fluorescent dye structurally equivalent to Alexa Fluor™ 660 (ThermoFisher). The dye demonstrates high fluorescence quantum yield, photostability, and aqueous solubility, with pH-independent fluorescence across a broad range (pH 4–11), providing consistent performance across diverse experimental conditions.

XFD660 is optimized for red laser excitation and is compatible with flow cytometers equipped with spectral detection systems. It provides robust and uniform labeling with high signal intensity and reproducibility, making it ideal for fluorescence imaging, flow cytometry, and other analytical techniques. XFD660 demonstrates versatility in labeling a wide range of targets, including cell surface, intracellular, and intranuclear antigens. Its spectral properties position it between XFD647 and XFD700, making it a valuable intermediate fluorophore for constructing complex multicolor panels and enabling precise experimental designs in advanced research workflows.

The azide derivative of XFD660 is widely used for labeling terminal alkynes on peptides, antibodies, and other biomolecules via click chemistry. It participates in copper-catalyzed azide-alkyne cycloaddition (CuAAC) with alkyne-containing molecules and strain-promoted alkyne-azide cycloaddition (SPAAC) with DBCO- or BCN-containing molecules.