XFD750 PEG4 DBCO

• Ex/Em: 752/776 nm
• Extinction coefficient: 240,000 cm^-1M^-1
• Reactive Group: DBCO
• Copper-Free Bioorthogonal Labeling: Enables rapid and efficient azide conjugation via copper-free SPAAC
• Bright & Stable: Offers intense, photostable fluorescence for labeling low-abundance targets
• Water Soluble: Minimizes aggregation, enhancing signal clarity for advanced imaging and live-cell studies

XFD750, manufactured by AAT Bioquest, is a bright near-infrared fluorescent dye structurally identical to Alexa Fluor™ 750 (ThermoFisher). It is efficiently excited by the 633 nm laser line and is compatible with the Cy7 filter set, making it well-suited for applications such as fluorescence microscopy and flow cytometry. The dye demonstrates excellent aqueous solubility and maintains pH stability across a broad range (pH 4–10), ensuring reliable and reproducible fluorescence signals under diverse experimental conditions. Its long-wavelength emission effectively reduces background autofluorescence, enhancing signal-to-noise ratios in complex biological samples, particularly in tissue imaging. Furthermore, XFD750 is widely utilized in stochastic optical reconstruction microscopy (STORM), providing exceptional performance in both dSTORM and nSTORM super-resolution imaging techniques.

The DBCO derivative of XFD750 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, XFD750 DBCO serves as an effective alternative to copper-dependent fluorescent alkynes.