sulfo-Cyanine5 streptavidin

Sulfo-Cyanine5 streptavidin is a fluorescent streptavidin conjugate built for robust biotin-based labeling workflows, combining high-affinity biotin binding with a Cy5-class far-red fluorophore for microscopy, imaging, and fluorescence readouts. This reagent is commonly used when a stable, multivalent biotin binder is needed to attach Cy5 signal to biotinylated targets such as nucleic acids, proteins, nanoparticles, and assay surfaces. The sulfonated dye format supports aqueous labeling conditions, making it practical for routine fluorescence experiments that rely on far-red detection.

1. Biotinylated Biomolecule Labeling

Sulfo-Cyanine5 streptavidin is frequently used to fluorescently tag biotinylated proteins, peptides, and complex biomolecular assemblies for downstream imaging and quantitative fluorescence assays. Researchers use it to generate Cy5-labeled conjugates without requiring covalent coupling of the fluorophore to the biomolecule, enabling straightforward labeling of biotinylated targets such as affinity reagents, detection antibodies, and engineered binding constructs. In typical workflows, the strong streptavidin-biotin interaction supports consistent probe presentation on the labeled biomolecule, which is particularly useful when maintaining labeling density and minimizing nonspecific dye conjugation is important.

2. Fluorescence Microscopy Staining

Sulfo-Cyanine5 streptavidin is widely applied in fluorescence microscopy workflows where far-red visualization of biotinylated structures is required. Cell biology and materials researchers often use it to stain biotinylated cell-surface markers, extracellular biomolecule layers, or biotin-functionalized substrates to map localization patterns with Cy5-compatible imaging channels. Because streptavidin is multivalent, this conjugate can provide strong signal for detecting sparse biotinylation patterns on fixed samples and prepared imaging platforms, supporting clear visualization in multicolor experiments where Cy5 emission is spectrally separated from common green/blue fluorophores.

3. Flow Cytometry Reporter Conjugates

Sulfo-Cyanine5 streptavidin is used to generate far-red fluorescent reporter conjugates for flow cytometry analysis of biotinylated targets on cells or beads. In assay development and immunoassay-style workflows, Cy5 signal is introduced by binding to biotinylated capture reagents or labeling handles, enabling researchers to quantify binding or surface presentation using standard cytometer laser/emission configurations for Cy5. This approach is particularly convenient when biotinylated antibodies, ligands, or engineered binding partners are already available, allowing rapid conversion into a fluorescent readout reagent for screening and characterization experiments.

4. Nucleic Acid Probe Construction

Sulfo-Cyanine5 streptavidin is commonly incorporated into nucleic acid analysis workflows that use biotinylated oligonucleotides as handles for fluorescence detection. Molecular biology teams use it to assemble Cy5-labeled nucleic acid probes or reporters by binding to biotinylated DNA/RNA targets, supporting fluorescence-based hybridization readouts and visualization of nucleic acid-containing complexes on membranes, gels, or imaging systems. The multivalent streptavidin format also supports signal amplification strategies at the probe level, which can be advantageous when constructing fluorescent nucleic acid reagents for research assays requiring far-red detection.