XFD680 PEG4 DBCO

• Ex/Em: 681/704 nm
• Extinction coefficient:184,000 cm^-1M^-1
• Superior Fluorescence Performance: High quantum yield, exceptional photostability, and pH-independent fluorescence across pH 4–11.
• Reactive Group: DBCO
• Copper-Free Bioorthogonal Labeling: Enables rapid and efficient azide conjugation via copper-free SPAAC
• High Water-Solubility: Prevents aggregation and enhances signal clarity for advanced imaging and live-cell applications

XFD680, manufactured by AAT Bioquest, is a bright near-infrared fluorescent dye structurally equivalent to Alexa Fluor™ 680 (ThermoFisher). It exhibits a high fluorescence quantum yield, excellent photostability, and superior aqueous solubility, ensuring consistent and reliable performance in various applications. Its pH-independent fluorescence across a broad range (pH 4–11) allows it to maintain stability under diverse experimental conditions. The dye also enables high molar ratio protein conjugation with minimal self-quenching, producing brighter conjugates and enhancing detection sensitivity. Its long-wavelength emission minimizes interference from autofluorescent background signals, enabling accurate detection in complex biological systems.

XFD680 is optimized for red laser excitation and is compatible with flow cytometers equipped with spectral detection systems. It delivers robust and uniform labeling, with high signal intensity and reproducibility, making it ideal for fluorescence imaging, flow cytometry, and other analytical techniques. XFD680 is also widely utilized in advanced applications such as multiplexed western blot detection and stochastic optical reconstruction microscopy (STORM), where its superior photophysical properties enhance resolution and sensitivity.

The DBCO derivative of XFD680 is a highly reactive cycloalkyne optimized for copper-free click chemistry (SPAAC, strain-promoted azide-alkyne cycloaddition). This derivative exhibits a significantly higher reaction rate with azides compared to other cyclooctynes and copper-catalyzed click reactions (CuAAC). Uniquely, DBCO does not react with tetrazines, allowing for its use in bioorthogonal reactions alongside trans-cyclooctenes and tetrazines. For applications where the presence of copper is problematic, XFD680 DBCO serves as an effective alternative to copper-dependent fluorescent alkynes.