Sulfo-Cyanine7 bis-NHS ester

Sulfo-Cyanine7 bis-NHS ester is a water-soluble, amine-reactive cyanine dye designed for efficient fluorescent labeling via NHS ester chemistry. With two NHS ester groups per molecule, it enables multivalent conjugation to lysine-containing biomolecules and amine-functional surfaces, producing bright far-red fluorescence for imaging workflows. Its sulfonate substituents support aqueous handling, making it a common reagent for preparing fluorescent conjugates used in microscopy, flow cytometry, and fluorescence-based assays.

1. Protein And Antibody Labeling

Sulfo-Cyanine7 bis-NHS ester is widely used by protein engineering and antibody conjugation teams to generate far-red fluorescent bioconjugates for imaging and analytical assays. Researchers typically label lysine-rich proteins, including antibodies, antibody fragments, enzymes, and affinity reagents, to create stable fluorescent conjugates for tracking binding and distribution. The bis-NHS format supports higher labeling density than mono-functional dyes, which is useful when strong far-red signal is needed for low-background fluorescence imaging and quantitative fluorescence readouts.

2. Cell Surface And Flow Cytometry Staining

Sulfo-Cyanine7 bis-NHS ester supports fluorescent labeling of cell-associated proteins and other amine-bearing targets for flow cytometry workflows where far-red detection is advantageous for reducing spectral overlap. In cell staining experiments, investigators use the dye to label cell-surface proteins and to generate fluorescent reagents for monitoring binding events, uptake proxies, or surface marker distribution in multiplex-compatible panels. The water-soluble sulfonated dye format helps maintain consistent staining in aqueous buffers commonly used in instrument-based analysis.

3. Biomaterial And Surface Functionalization

Sulfo-Cyanine7 bis-NHS ester is used in biomaterials research to fluorescently tag amine-functional polymers, hydrogels, and surfaces so that material localization, coating uniformity, and trafficking can be visualized. By reacting with surface-exposed primary amines, the bis-NHS dye can be incorporated into coatings and functional layers used in microscopy and fluorescence imaging studies of engineered materials. This approach is particularly useful when the labeling needs to remain compatible with aqueous sample handling and when far-red fluorescence provides improved imaging contrast over shorter-wavelength dyes.

4. Fluorescent Probe And Conjugate Construction

Sulfo-Cyanine7 bis-NHS ester is frequently employed as a labeling building block for constructing fluorescent probe conjugates and assay reagents where a cyanine far-red reporter is required. Chemical biology groups use the dye to prepare fluorescent conjugates for downstream assay development, including labeling of nucleic-acid-binding proteins, affinity reagents, and other lysine-containing components that form the recognition element of a fluorescent assay. The bis-NHS functionality supports conjugate synthesis with controlled attachment to amine-bearing partners, enabling consistent far-red reporting in fluorescence microscopy and plate-based fluorescence measurements.