Sulfo-Cy5 Azide | CAS 1481447-40-8

Sulfo-Cy5 Azide is a water-soluble Cy5 azide building block designed for copper-free click chemistry workflows that install a bright, far-red fluorophore onto biomolecules, polymers, and surfaces. As a sulfonated dye, it is commonly used to generate stable fluorescent conjugates with improved aqueous handling for imaging and assay development, including applications where background fluorescence and labeling efficiency matter. Its azide functionality enables straightforward incorporation into labeled constructs that are compatible with fluorescence microscopy and fluorescence-based readouts.

1. Biomolecule Labeling

Sulfo-Cy5 Azide is widely used as a fluorescent labeling reagent in bioconjugation workflows where researchers need far-red Cy5 signal for tracking proteins, peptides, and other biomolecular targets. In typical labeling pipelines, the azide handle is coupled via click chemistry to complementary cyclooctyne/DBCO-bearing partners to produce dye-labeled conjugates for binding studies, reagent characterization, and molecular imaging reagent development. The sulfonated Cy5 scaffold supports aqueous conjugation and helps maintain fluorescence in water-based buffers commonly used in biochemical assays and imaging experiments.

2. Fluorescence Microscopy Tracing

Sulfo-Cy5 Azide is frequently incorporated into fluorescent probes and labeling reagents for fluorescence microscopy experiments that benefit from far-red emission to reduce interference from cellular autofluorescence. Researchers use Cy5-azide labeling to visualize biomolecule localization, track conjugate uptake or binding to assay surfaces, and follow labeled material distribution in fixed or prepared samples. The azide-to-cyclooctyne click handle is particularly useful when labeling needs to be performed under conditions compatible with sensitive biomolecular components, enabling construction of microscopy-ready fluorescent conjugates for cell imaging, microtissue staining, and imaging-based binding assays.

3. Flow Cytometry Conjugates

Sulfo-Cy5 Azide supports fluorescence labeling strategies for flow cytometry reagent development, especially when a far-red detection channel is desired for multiplexing or for minimizing spectral overlap with common fluorophores. Laboratories use Cy5-azide click conjugation to generate stained biomolecule conjugates such as antibody or ligand derivatives (via appropriate cyclooctyne intermediates) for cell-surface binding assays and labeling controls. The water-soluble sulfonated dye format helps streamline conjugate preparation in aqueous staining buffers used for cytometry workflows, supporting consistent staining and reproducible readouts across experiments.

4. Polymer And Surface Functionalization

Sulfo-Cy5 Azide is used to introduce fluorescent tags into polymer materials and functional surfaces for materials imaging and surface characterization. By clicking the azide dye onto cyclooctyne-modified polymers, hydrogels, or coated substrates, researchers can create fluorescently traceable materials that enable visualization of coating uniformity, diffusion or adsorption behavior, and spatial distribution on engineered surfaces. This approach is also applied in biomaterials science to generate fluorescently labeled scaffolds and to support imaging-based evaluation of biomolecule-material interactions in assay formats that rely on far-red fluorescence detection.