ATTO 620 DBCO

• Ex/Em: 619/641 nm
• Extinction coefficient: 120,000 cm^-1M^-1
• Reactive group: DBCO
• Copper-Free Bioorthogonal Labeling: Enables efficient azide conjugation via SPAAC without copper, ideal for sensitive systems
• High Quantum Yield & Stability: Delivers bright, stable fluorescence under prolonged light exposure, temperature changes, and across pH 2–11
• Temperature-Dependent Fluorescence: Enables precise thermal mapping in live cells, protein studies, and reaction monitoring

ATTO 620 is a bright-red fluorescent dye, characterized by its strong absorption, exceptional photo and thermal stability, and temperature-dependent fluorescence. It demonstrates moderate hydrophilicity and optimal excitation within the 600-630 nm wavelength range. The dye maintains stable fluorescence over a wide pH range (2-11), allowing for its use in diverse experimental conditions. Upon conjugation to a substrate, ATTO 620 becomes cationic, carrying a net positive charge of +1. These properties make ATTO 620 particularly suitable for high-precision applications, including single-molecule detection and super-resolution microscopy techniques such as PALM, dSTORM, and STED. Additionally, it is compatible with flow cytometry (FACS), fluorescence in situ hybridization (FISH), and various other biological assays.

The DBCO derivative of ATTO 620 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, ATTO 620 DBCO serves as an effective alternative to copper-dependent fluorescent alkynes.