9-[2-Carboxy-5(or 6)-isothiocyanatophenyl]-3,6-bis(diethylamino)xanthylium, chloride | CAS 36877-69-7

9-[2-Carboxy-5(or 6)-isothiocyanatophenyl]-3,6-bis(diethylamino)xanthylium, chloride is a xanthylium-based fluorescent dye bearing an isothiocyanate group for covalent labeling and a carboxylate handle for conjugate design. In fluorescence workflows, it is typically used to generate stable, dye-labeled biomolecules and imaging reagents where strong visible emission and robust covalent attachment are required. The dye's ionic, conjugation-friendly structure supports its use in labeling strategies for microscopy and fluorescence-based analytical assays.

1. Protein And Peptide Labeling

9-[2-Carboxy-5(or 6)-isothiocyanatophenyl]-3,6-bis(diethylamino)xanthylium, chloride is widely used in fluorescence labeling of proteins and peptides for research-grade imaging and assay development. The isothiocyanate functionality enables covalent attachment to primary amines on lysine residues and N-termini, supporting preparation of fluorescent antibody conjugates, enzyme conjugates, and labeled affinity reagents used in binding studies. Researchers commonly incorporate this dye-labeled biomaterial into fluorescence microscopy, plate-based fluorescence assays, and instrument-based characterization workflows where stable conjugation reduces dye loss during washing or incubation steps.

2. Fluorescence Microscopy Tracing

9-[2-Carboxy-5(or 6)-isothiocyanatophenyl]-3,6-bis(diethylamino)xanthylium, chloride is used as a fluorescent labeling reagent to visualize biomolecular localization and transport in microscopy experiments. Covalently labeled proteins, peptides, or other amine-containing targets prepared with the dye can be tracked in fixed or processed samples to map distribution patterns relevant to cell biology and molecular imaging workflows. The dye's xanthylium chromophore is leveraged to produce bright fluorescence signals for qualitative and semi-quantitative imaging, including studies where conjugate stability during staining and wash steps is important.

3. Biomolecule Conjugate Standards

9-[2-Carboxy-5(or 6)-isothiocyanatophenyl]-3,6-bis(diethylamino)xanthylium, chloride is also used in the preparation of fluorescent conjugates that serve as internal references or calibration materials in fluorescence measurement workflows. Laboratories generating labeled biomolecule standards rely on the dye's covalent attachment to create reproducible fluorescent reagents for method development, instrument setup, and comparative assay optimization. The presence of a carboxylate group supports conjugate engineering strategies where controlled dye presentation and downstream coupling to carriers or surfaces are part of the reagent design.

4. Surface And Material Functionalization

9-[2-Carboxy-5(or 6)-isothiocyanatophenyl]-3,6-bis(diethylamino)xanthylium, chloride can be incorporated into biomaterial and surface functionalization programs that require covalently attached fluorescent tags. In materials science and chemical biology workflows, the dye is used to label amine-functionalized polymers, coatings, or scaffold materials to create fluorescently traceable surfaces for adsorption studies, immobilization verification, and imaging-based characterization. The resulting fluorescent materials are used to confirm coating uniformity, monitor binding of fluorescently labeled biomolecules to engineered substrates, and support development of fluorescence readout platforms for research applications.