Sulfo-Cyanine7 NHS ester

Sulfo-Cyanine7 NHS ester is a water-soluble, sulfonated near-infrared cyanine dye designed for amine-reactive fluorescent labeling via its N-hydroxysuccinimide (NHS) ester functionality. The sulfonate group helps maintain aqueous compatibility, while the Cy7 chromophore enables fluorescence imaging in the far-red/near-infrared region for reduced background in many optical setups. Researchers use this reagent to prepare fluorescent conjugates for microscopy, cell-based assays, and imaging workflows that benefit from NIR detection.

1. Protein And Antibody Labeling

Sulfo-Cyanine7 NHS ester is widely used for covalent fluorescent labeling of proteins, including antibodies, antibody fragments, enzymes, and affinity reagents, through reaction with accessible primary amines on the biomolecule. This labeling format supports construction of fluorescent immunoprobes and detection reagents for binding studies, target visualization, and fluorescence-based readouts in standard plate readers and optical imaging systems. The sulfonated dye design is particularly convenient when conjugates must remain water-compatible for downstream assay preparation and handling.

2. Fluorescence Microscopy Labeling

Sulfo-Cyanine7 NHS ester is commonly applied to generate far-red fluorescent staining reagents for cellular and subcellular imaging experiments where NIR-channel acquisition is advantageous. After conjugation to amine-containing biomolecules (e.g., carrier proteins, targeting ligands, or secondary labeling reagents), the resulting Cy7 conjugates can be used to visualize labeled structures with reduced spectral overlap compared with many visible fluorophores. Imaging workflows often include fixed-cell microscopy and multi-channel experiments where far-red detection improves background performance and simplifies channel separation.

3. Flow Cytometry Conjugate Preparation

Sulfo-Cyanine7 NHS ester is used in flow cytometry reagent development to prepare fluorescently labeled biomolecule conjugates for cell-surface or intracellular labeling strategies that rely on far-red detection. Conjugates generated from amine-reactive labeling are frequently incorporated into antibody-based staining panels, enabling instrument-compatible detection in Cy7/near-infrared channels. This reagent format is also useful for producing standardized fluorescent labeling reagents for method development, gating optimization, and comparative studies across experimental conditions.

4. NIR Imaging Probe Development

Sulfo-Cyanine7 NHS ester supports molecular imaging reagent development by enabling rapid fluorescent tagging of amine-functional ligands and carrier molecules used in optical imaging experiments. Researchers often prepare Cy7-labeled conjugates for tracking distribution, localization, and binding behavior in imaging platforms that detect far-red/near-infrared fluorescence. The NHS ester chemistry provides a practical route to generate fluorescent probes for assay development and imaging reagent libraries, including labeling of biomolecular constructs used in fluorescence-guided characterization workflows.