XFD514, manufactured by AAT Bioquest, is a green-fluorescent dye structurally similar to Alexa Fluor™ 514 (Thermo Fisher). It is characterized by high photostability and exceptional brightness, making it highly suitable for advanced imaging and flow cytometry applications. The dye is water-soluble and remains pH-insensitive within a broad range (pH 4–10), ensuring consistent fluorescence performance across diverse experimental conditions. XFD514 offers robust and reliable labeling, enabling precise and reproducible results in fluorescence-based assays. It also serves as an effective replacement for rhodamine 6G in applications requiring enhanced performance.

The DBCO derivative of XFD514 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, XFD514 DBCO serves as an effective alternative to copper-dependent fluorescent alkynes.