Sulfo-Cyanine7 maleimide | CAS 2183440-60-8

Sulfo-Cyanine7 maleimide is a water-soluble, maleimide-functionalized cyanine dye designed for thiol-reactive bioconjugation. Its anionic sulfonate substituents support aqueous labeling workflows, while the maleimide group enables efficient coupling to accessible cysteine residues on proteins, peptides, and other thiol-bearing biomolecules. The resulting Cy7-labeled conjugates are commonly used for fluorescence imaging and near-infrared channel readouts where deep-tissue-compatible excitation/emission settings are required.

1. Protein Thiol Labeling

Sulfo-Cyanine7 maleimide is widely used by protein engineering and chemical biology groups to generate fluorescently labeled antibodies, enzymes, and affinity reagents through thiol-directed conjugation. Researchers typically introduce single-cysteine sites (or use native accessible cysteines) to control dye loading and preserve biological activity for downstream assays. The sulfonated Cy7 dye format supports aqueous handling during conjugate preparation and helps maintain labeling performance in typical buffer conditions used for binding and imaging experiments.

2. Peptide And Biomolecule Tagging

Sulfo-Cyanine7 maleimide supports fluorescent tagging of peptides, peptide ligands, and other thiol-containing biomolecules used in molecular imaging and fluorescence-based binding studies. In practice, teams developing labeled ligands for receptor-binding or target localization experiments rely on the maleimide handle to attach the Cy7 fluorophore to defined cysteine positions, enabling consistent probe construction for microscopy and optical readouts. The resulting conjugates are also used as tracer reagents in biochemical workflows requiring a robust near-infrared fluorescence signal.

3. NIR Fluorescence Imaging Probes

Sulfo-Cyanine7 maleimide is frequently incorporated into imaging probe development for fluorescence microscopy and optical imaging experiments that use Cy7-compatible excitation/emission detection. Molecular imaging workflows often benefit from the dye's bright cyanine characteristics and the water-soluble sulfonate architecture, which can reduce nonspecific aggregation during probe preparation. Researchers use Cy7-thiol conjugates to visualize labeled biomolecules, track binding/uptake behaviors in cultured systems, and build fluorescent standards for instrument method development.

4. Surface And Material Functionalization

Sulfo-Cyanine7 maleimide is used in biomaterials and surface chemistry workflows to create dye-functionalized surfaces and nanoparticle coatings via thiol-reactive coupling. Materials scientists commonly immobilize thiol-bearing linkers on hydrogels, polymer films, or engineered nanoparticles and then attach the Cy7 maleimide to generate fluorescently traceable constructs for microscopy, imaging-based characterization, and material tracking studies. The sulfonated dye format helps maintain aqueous compatibility during surface modification steps, supporting reproducible labeling of material platforms used in chemical biology and materials research.