Sulfo-Cyanine5 bis-NHS ester

Sulfo-Cyanine5 bis-NHS ester is a water-soluble, amine-reactive cyanine dye designed for efficient fluorescent labeling of biomolecules and polymers through NHS ester chemistry. As a Cy5-based fluorophore, it provides strong red fluorescence for microscopy and fluorescence readouts, while the bis-NHS format enables dual-site conjugation to primary amines for higher labeling density. The sulfonated scaffold supports aqueous handling and conjugate preparation for fluorescence imaging workflows.

1. Protein And Antibody Labeling

Sulfo-Cyanine5 bis-NHS ester is widely used in labeling workflows for proteins and antibody conjugates where red fluorescence from the Cy5 dye is required for imaging or assay development. Researchers typically employ the bis-NHS functionality to attach the fluorophore to lysine residues on antibodies, enzymes, or carrier proteins, producing fluorescent conjugates for binding studies, reagent tracking, and fluorescence-based quantification. The sulfonate-containing dye structure supports aqueous conjugation and downstream handling, making it practical for preparing labeled bioreagents used in microscopy and plate-based fluorescence assays.

2. Fluorescence Microscopy Tracing

Sulfo-Cyanine5 bis-NHS ester supports cellular and biomaterial imaging experiments that rely on robust red-channel detection. In fluorescence microscopy workflows, the reagent is commonly used to generate Cy5-labeled probes from amine-containing targeting ligands, extracellular matrix components, or surface-associated biomolecules, enabling visualization of binding, localization, and transport in complex samples. The bis-NHS format can increase labeling density on the conjugate, which is particularly useful when preparing fluorescent tagging reagents for multicolor imaging panels where Cy5 provides a distinct spectral window.

3. Flow Cytometry Labeling Reagents

Sulfo-Cyanine5 bis-NHS ester is used to construct fluorescent labeling reagents for flow cytometry and fluorescence-activated cell sorting experiments that detect red fluorescence signals. By conjugating the dye to amine-bearing antibodies, peptides, or other binding proteins, researchers create Cy5-tagged reagents for cell-surface staining, receptor binding studies, and fluorescence-based population analysis. The sulfonated, water-soluble dye design helps streamline conjugate preparation in aqueous buffers, supporting consistent reagent handling for routine cytometry workflows.

4. Polymer And Surface Functionalization

Sulfo-Cyanine5 bis-NHS ester is also applied in materials research to fluorescently functionalize amine-containing polymers and surfaces for imaging-guided studies. In biomaterials and surface engineering workflows, the bis-NHS chemistry enables covalent attachment to amine groups on polymer backbones, coating layers, or functionalized scaffolds, generating Cy5-labeled materials that can be tracked by fluorescence microscopy or imaged in situ. This approach is commonly used to visualize coating uniformity, material distribution, and biomolecule-material interactions in engineered systems where stable covalent dye incorporation is required.