ATTO 680 Tetrazine

• Ex/Em: 679/696 nm
• Extinction coefficient: 125,000 cm^-1M^-1
• Reactive group: Tetrazine
• Click Chemistry Conjugation: Offers high yield and rapid, copper-free labeling of TCO-modified biomolecules
• High Quantum Yield & Stability: Provides bright fluorescence with high photostability and thermal resilience
• Zwitterionic: Minimizes non-specific binding to biological surfaces, reducing background noise in live-cell imaging and super-resolution microscopy

ATTO 680 is a far-red fluorescent dye characterized by its strong absorption, high photo and thermal stability, and good aqueous solubility. It is optimally excited within the 645-695 nm wavelength range, which aligns with the 670 nm line of diode laser and the 676 nm line of Krypton-Ion laser. As a zwitterionic compound, ATTO 680 remains electrically neutral when conjugated to biomolecules or other substrates. Its strong electron-accepting properties result in efficient fluorescence quenching by electron donors such as guanine and tryptophan. These properties make ATTO 680 ideal for precise applications including single-molecule detection and super-resolution microscopy techniques like PALM, dSTORM, and STED. Furthermore, ATTO 680 is compatible with flow cytometry (FACS), fluorescence in situ hybridization (FISH), and a variety of other biological assays, making it a versatile tool in advanced fluorescence-based research.

ATTO 680 tetrazine is particularly useful for labeling TCO-modified biomolecules under copper-free conditions. It reacts with TCO-functionalized molecules, forming a stable conjugate via a dihydropyrazine moiety. This click reaction is favored over others due to its extremely fast kinetics and higher yields under mild reaction conditions, making it a popular choice for researchers.