XFD700 Tetrazine

• Ex/Em: 696/719 nm
• Extinction coefficient: 192,000 cm^-1M^-1
• Reactive Group: Tetrazine
• Click Chemistry Conjugation: Provides rapid, copper-free labeling of TCO-modified biomolecules
• Moderate Brightness: Suitable for high-abundance targets, preserving brighter dyes for low-abundance detection.
• Water Soluble: Minimizes aggregation, enhancing signal clarity for advanced imaging and live-cell studies
• Panel Optimization: Enhances spectral resolution between APC and APC-iFluor® 780 in multicolor assays.

XFD700, manufactured by AAT Bioquest, is a near-infrared fluorescent dye structurally identical to Alexa Fluor™ 700 (ThermoFisher). It is optimally excited by 633–640 nm laser lines and offers a relatively low fluorescence intensity, making it particularly well-suited for direct imaging of high-abundance targets in both microscopy and flow cytometry. This allows researchers to allocate brighter dyes for detecting lower-abundance antigens, improving overall panel design. XFD700 exhibits excellent aqueous solubility and maintains consistent fluorescence stability across a broad pH range (pH 4–10), ensuring robust and reproducible performance under diverse experimental conditions. Its long-wavelength emission effectively minimizes background autofluorescence, leading to enhanced signal-to-noise ratios, especially in complex biological samples such as tissues. In multicolor flow cytometry panels, XFD700 serves as an ideal option between APC and APC-iFluor® 780, enabling better resolution in complex assays.

XFD700 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.