XFD488 PEG4 DBCO

• Ex/Em: 499/520 nm
• Extinction coefficient: 71,000 cm^-1M^-1
• Reactive Group: DBCO
• Copper-Free Bioorthogonal Labeling: Enables rapid and efficient azide conjugation via copper-free SPAAC
• Bright and Stable: Offers high fluorescence intensity, photostability, and consistent performance across pH 4—10
• Hydrophilic PEG4 Spacer: Enhances solubility and minimizes steric hindrance for impvoed biocompatibility

XFD488, manufactured by AAT Bioquest, is structurally identical to Alexa Fluor® 488 (ThermoFisher). XFD488 PEG4 DBCO is a green-fluorescent dye characterized by strong absorption, high photostability, and pH-stable fluorescence over a broad range (pH 4-11). The incorporation of a PEG4 linker enhances its aqueous solubility, and it is efficiently excited by the 488 nm line of an argon-ion laser. Its superior brightness and stability make it particularly well-suited for applications in both imagining and flow cytometry.

The DBCO derivative of XFD488 is a highly reactive cycloalkyne optimized for copper-free click chemistry (SPAAC, strain-promoted azide-alkyne cycloaddition). This derivative exhibits a higher reaction rate with azides compared to other cyclooctynes and traditional copper-catalyzed azide-alkyne cycloaddition (CuAAC). Importantly, DBCO does not react with tetrazines, making it compatible with bioorthogonal reactions involving trans-cyclooctenes and tetrazines. This feature allows XFD488 PEG4 DBCO to serve as an effective alternative to copper-dependent fluorescent alkynes in environments where copper ions may interfere with biological processes.