sulfo-Cyanine3.5 azide

Sulfo-Cyanine3.5 azide is a sulfonated cyanine azide designed for copper-free click chemistry workflows that install a Cy3.5-like fluorophore handle onto biomolecules and materials. Its anionic sulfonate functionality supports aqueous labeling and fluorescent tracking in biological assay development, where the dye's red-shifted emission is leveraged for multicolor imaging and probe construction.

1. Biomolecule Click Labeling

Sulfo-Cyanine3.5 azide is used by chemical biology and glycobiology groups to fluorescently label proteins, peptides, and other primary biomolecules that have been engineered to carry a complementary click partner (commonly strained alkynes or cyclooctynes). Researchers typically incorporate it into labeling workflows for binding studies, reagent characterization, and fluorescence-based readouts, including tracking conjugate formation and monitoring labeling efficiency during probe or antibody conjugate development. The sulfonated, water-compatible dye format helps maintain fluorescence in aqueous buffers commonly used for bioconjugation and downstream assay handling.

2. Fluorescent Probe Construction

Sulfo-Cyanine3.5 azide serves as a fluorophore-building block for constructing Cy3.5-based fluorescent probes used in microscopy and plate-based fluorescence assays. Teams developing targeted or modular probes attach the azide dye to a scaffold bearing the complementary click functionality, enabling rapid assembly of fluorescent conjugates for molecular imaging reagent development, affinity reagent optimization, and assay controls. This approach is frequently used when probe architecture must be diversified (for example, swapping targeting ligands or linkers) while keeping a consistent cyanine fluorophore reporting group for comparative studies.

3. Surface And Polymer Functionalization

Materials and biomaterials researchers use Sulfo-Cyanine3.5 azide to introduce a fluorescent tag onto polymer surfaces, hydrogels, and functional coatings through click-compatible immobilization strategies. In these workflows, the dye-modified surfaces become tools for studying adsorption, coating uniformity, and biomaterial interactions under aqueous conditions, with fluorescence readout enabling visualization and quantitative monitoring. The sulfonated cyanine format supports labeling in buffer-based protocols used for surface modification and subsequent imaging of material interfaces.

4. Cell Imaging Labeling Studies

Sulfo-Cyanine3.5 azide is applied in cellular imaging experiments where fluorescent labeling of biomolecule conjugates is required for localization and trafficking studies. Researchers generate fluorescent conjugates via click coupling, then use them as imaging reagents in microscopy experiments to follow labeled targets in fixed or permeabilized preparations, or to visualize extracellular binding events when the conjugate is introduced as an imaging reagent. The Cy3.5-like emission profile is commonly chosen to support multicolor panels and to separate red-channel signals from green fluorophores in fluorescence microscopy work.