XFD660 Tetrazine

• 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: Tetrazine
• Click Chemistry Conjugation: Provides rapid, copper-free labeling of TCO-modified biomolecules
• 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.

XFD660 tetrazine is particularly useful for labeling TCO-modified biomolecules under copper-free conditions. It reacts with TCO-functionalized molecules, forming a stable conjugate via a dihydropyrazine moiety. This click reaction is favored over others due to its extremely fast kinetics and higher yields under mild reaction conditions, making it a popular choice for researchers.