Sulfo-Cyanine5 alkyne

Sulfo-Cyanine5 alkyne is a water-soluble Cy5-based fluorescent labeling reagent bearing a terminal alkyne handle for copper-free click chemistry workflows. Its bright far-red emission makes it well suited for fluorescence imaging and labeling of biomolecules and materials where low background and aqueous compatibility are important. The alkyne functionality enables efficient attachment to azide-bearing targets, including biomolecule conjugates, affinity reagents, and polymer or surface coatings used in fluorescence microscopy and analytical assays.

1. Biomolecule Click Labeling

Sulfo-Cyanine5 alkyne is commonly used to fluorescently tag proteins, peptides, and other biomolecules in bioconjugation workflows that rely on azide-functional partners. Researchers incorporate the reagent into labeling strategies for tracking binding, following conjugate assembly, and visualizing biomolecular localization in aqueous buffers. The sulfonated Cy5 scaffold supports far-red imaging with reduced sensitivity to autofluorescence compared with shorter-wavelength dyes, which is advantageous for complex biological samples and multi-component labeling schemes.

2. Fluorescence Microscopy Tracing

Sulfo-Cyanine5 alkyne supports fluorescence microscopy studies where far-red signal is used to trace labeled biomolecules in cells, tissues, or biomaterial systems. In practice, it is frequently used to build fluorescent conjugates for imaging experiments after click attachment to azide-tagged targeting ligands, antibodies, or cell-interaction reagents. The resulting Cy5 fluorescence is leveraged for localization studies, co-localization experiments, and wash-resistant labeling formats that benefit from the dye's aqueous compatibility and strong emission in the red spectral region.

3. Flow Cytometry Conjugates

Sulfo-Cyanine5 alkyne is used in flow cytometry reagent development when far-red detection channels are preferred for minimizing spectral overlap and background. After click conjugation to azide-bearing affinity reagents, the dye-labeled constructs enable quantitative measurement of binding to cell-associated targets in suspension assays. This approach is widely adopted in assay development and phenotyping workflows where fluorescent labeling consistency and compatibility with standard cytometry optics are required, particularly when multiplexing with other fluorophores.

4. Surface And Polymer Functionalization

Sulfo-Cyanine5 alkyne is also applied to fluorescently functionalize azide-containing surfaces, coatings, and polymeric materials for imaging and materials characterization. Teams use the reagent to create labeled biomaterial interfaces that can be imaged by fluorescence microscopy to assess coating uniformity, spatial patterning, and material-biomolecule interactions. The water-soluble sulfonated Cy5 structure helps maintain labeling performance in aqueous environments used for material incubation and washing steps, supporting robust visualization of engineered interfaces.