AAT Bioquest offers a comprehensive collection of specialty fluorescent dyes engineered for advanced research applications. These dyes span multiple wavelength ranges and include proprietary formulations optimized for photostability, brightness, and reduced pH sensitivity. Whether you need photostable far-red fluorophores for single-molecule detection, probes for intracellular trafficking studies, or oligonucleotide labeling dyes for genetic analysis, this catalog provides the tools essential for fluorescence microscopy, flow cytometry, and molecular biology research.

xtraFluor™ Violet 420 (XV420) is an high-brightness violet laser-excitable fluorophore designed for flow cytometry and multicolor panel applications. With excitation well-matched to the 405 nm violet laser and emission at ~420 nm, XV420 can serve as a direct replacement for BD Horizon Brilliant™ Violet 421 (BV421). The dye delivers exceptional brightness, making it ideal for detecting low-abundance markers in complex multicolor flow cytometry experiments.

zFluor™ dyes are developed to provide high photostability at their respective wavelengths. These dyes are ideal for demanding applications including single-molecule detection, advanced fluorescence microscopy, and extended time-lapse imaging. zFluor™ dyes exhibit excellent thermal stability and maintain consistent performance under intense illumination, making them suitable for high-resolution studies where other dyes would rapidly photobleach.

These dyes are specifically engineered for nucleic acid applications including DNA sequencing, qPCR, fragment analysis, and SNP genotyping. The 6-isomer dyes (6-HEX, 6-TET, 6-VIC, 6-NED) are industry standards for multicolor capillary electrophoresis. Helix Fluor™ dyes provide cost-effective alternatives with improved stability, while Sunnyvale Red™ offers extended shelf life compared to traditional ROX dyes.

Bodi Fluor™ dyes are chemically identical to their BODIPY™ counterparts, offering the comparable properties at competitive pricing. These dyes feature high cell permeability, excellent extinction coefficients, and low pH-sensitivity fluorescence. The narrow emission bandwidth and lipophilic character make them ideal for membrane studies, lipid trafficking research, and applications where spectral resolution is critical. Unlike xanthene dyes, Bodi Fluor™ fluorescence remains stable across physiological pH ranges.

Dansyl dyes are classic environment-sensitive fluorophores characterized by large Stokes shifts (~180 nm) and solvatochromic properties. The fluorescence quantum yield and emission maximum shift dramatically depending on the local environment polarity, making these dyes invaluable for studying protein conformational changes, ligand binding events, and membrane dynamics. Dansyl chloride is non-fluorescent until conjugated to amines, providing built-in background reduction.

NBD (7-nitrobenz-2-oxa-1,3-diazole) dyes are compact fluorophores widely used for labeling peptides, proteins, lipids, and small molecules. NBD-Cl and NBD-F are non-fluorescent until conjugated to amines or thiols, generating bright green fluorescent adducts. The NBD-X derivatives incorporate a spacer that improves conjugation yields with biopolymers. NBD fluorescence is highly environment-sensitive, decreasing significantly in aqueous environments, which can be advantageous for detecting membrane-bound versus cytosolic species.

pH-sensitive fluorescent dyes enable real-time monitoring of pH changes in biological systems. This collection includes ratiometric indicators (SNARF™-1) that allow quantitative pH measurements independent of dye concentration, and acidotropic probes (Protonex™) that accumulate in acidic compartments for studying endosomal trafficking, lysosomal function, and receptor internalization.

SNARF™-1 exhibits a distinct pH-dependent emission shift, transitioning from yellow-orange fluorescence under acidic conditions to deep red fluorescence at basic pH. With a pKa of ~7.5, it is optimized for detecting pH changes within the physiological range (pH 7–8). The ratiometric readout enables accurate pH quantification regardless of dye loading, photobleaching, or optical path length variations.

Protonex™ dyes are minimally fluorescent at neutral/basic pH and become maximally fluorescent in acidic environments. When conjugated to antibodies or ligands targeting cell surface receptors, Protonex™ remains non-fluorescent at the cell surface but becomes highly fluorescent upon receptor internalization and entry into acidic endosomes/lysosomes. This "turn-on" mechanism enables direct visualization of receptor-mediated endocytosis and provides excellent signal-to-background ratios.

These calibrated dye sets are designed for developing and validating fluorescence instruments including microplate readers, flow cytometers, and imaging systems. Each set contains multiple spectrally distinct dyes that are efficiently excited by a single laser wavelength, enabling multicolor detection system development and quality control.

Selecting the appropriate reactive dye depends on the functional groups available on your target molecule. The table below summarizes common reactive groups and their target chemistries.