sulfo-Cyanine3.5 alkyne

Sulfo-Cyanine3.5 alkyne is a sulfonated cyanine fluorophore bearing a terminal alkyne for copper-catalyzed azide-alkyne cycloaddition (CuAAC) bioconjugation. Its water-soluble, membrane-compatible dye format makes it practical for fluorescent labeling workflows where a reactive handle is required to attach the fluorophore to biomolecules, linkers, or functionalized materials. In imaging and assay development, the cyanine dye provides strong fluorescence in the red region, enabling sensitive visualization of labeled targets in microscopy and fluorescence-based readouts.

1. Biomolecule Fluorescent Labeling

Sulfo-Cyanine3.5 alkyne is used to generate fluorescent bioconjugates for protein, peptide, and other biomolecule labeling strategies that rely on azide-functional partners. Researchers typically incorporate azide groups into antibodies, affinity ligands, peptides, or engineered proteins and then use the alkyne dye to install the Cy3.5 fluorophore via click chemistry, producing conjugates suitable for fluorescence microscopy and plate-based fluorescence assays. The sulfonated dye design supports aqueous conjugation and downstream handling, which is especially helpful when conjugates must remain stable and dispersible in labeling buffers.

2. Targeted Probe Construction

Sulfo-Cyanine3.5 alkyne is frequently selected for building fluorescent probe reagents where a defined dye-to-target architecture is required. In chemical biology and molecular imaging tool development, teams use azide-bearing targeting vectors such as small-molecule scaffolds, receptor-binding peptides, or nucleic-acid-adjacent linkers, then click the Cy3.5 alkyne dye to produce imaging-ready constructs. This approach is commonly used to create labeling reagents for tracking binding, localization, and uptake in cell-based experiments, as well as for constructing modular probe libraries where the same fluorophore is swapped onto different targeting motifs.

3. Surface And Nanomaterial Functionalization

Sulfo-Cyanine3.5 alkyne supports fluorescent surface modification of biomaterials, nanoparticles, and engineered surfaces when the substrate is prepared with azide functionality. Materials scientists and biointerfaces researchers use click-compatible dye installation to create labeled coatings, tracking tags for nanoparticle uptake studies, or fluorescent markers for material characterization. The dye's sulfonate group helps maintain dispersibility during functionalization and washing steps, enabling reproducible incorporation into aqueous workflows used for microscopy imaging of labeled materials and for fluorescence-based quantification of surface labeling.

4. Fluorescence Imaging Assay Development

Sulfo-Cyanine3.5 alkyne is applied in fluorescence assay development when a reactive fluorophore is needed to create labeled standards, reporters, or assay components. In assay development workflows, the alkyne dye is clicked onto azide-bearing reporter scaffolds to generate fluorescent conjugates used for monitoring binding events, tracking reagent distribution, or validating workflow performance in microscopy and fluorescence plate readers. The red-emitting cyanine format aligns well with common fluorescence imaging setups, allowing researchers to design experiments that separate Cy3.5-labeled signals from other fluorophores in multicolor studies when spectral overlap is managed through instrument filter selection.