Cy5-NHS ester tetrafluoroborate | CAS 1263093-76-0

Cy5-NHS ester tetrafluoroborate is a reactive cyanine dye designed for fluorescent labeling through NHS ester chemistry, enabling efficient coupling to primary amines on proteins, peptides, and other amine-containing biomolecules. Its far-red Cy5 fluorescence supports low-background imaging workflows in fluorescence microscopy and fluorescence-based readouts, where spectral separation from common green/orange channels is advantageous for multicolor experiments.

1. Protein And Antibody Labeling

Cy5-NHS ester tetrafluoroborate is used by protein chemistry and immunoassay teams to generate far-red fluorescent conjugates for binding studies, imaging, and assay development. The NHS ester reactivity toward lysine side-chain amines and N-terminal groups allows straightforward preparation of Cy5-labeled antibodies, antibody fragments, and affinity reagents for fluorescence microscopy, Western blot visualization, and fluorescence-based binding assays. Far-red emission is particularly helpful when background autofluorescence from biological samples is a concern, supporting clearer visualization in cell and tissue imaging workflows.

2. Peptide and Biomolecule Conjugation

Cy5-NHS ester tetrafluoroborate is commonly employed in chemical biology and biomaterials research to label peptides and other amine-bearing biomolecules used as targeting ligands, uptake probes, or affinity handles. Researchers use the dye to prepare fluorescent peptide conjugates for tracking binding and internalization, and to create labeled components for constructing multicomponent molecular imaging reagents. The amine-targeting coupling chemistry supports flexible downstream conjugate design for experiments that require a stable far-red fluorescent tag compatible with standard fluorescence instrumentation.

3. Fluorescence Microscopy Tracing

Cy5-NHS ester tetrafluoroborate is used in fluorescence microscopy to visualize labeled biomolecules in fixed-cell and in vitro imaging experiments where far-red channels reduce spectral overlap with common fluorophores. Imaging teams incorporate Cy5 conjugates to track distribution of labeled proteins, peptides, or macromolecular complexes across cellular compartments and experimental surfaces. The dye's bright far-red emission supports clear detection in confocal and widefield microscopy setups, including multicolor labeling schemes that benefit from Cy5 spectral separation.

4. Flow Cytometry Fluorescent Labeling

Cy5-NHS ester tetrafluoroborate is applied by flow cytometry users to prepare far-red fluorescent conjugates for cell-surface or intracellular labeling experiments that rely on amine-reactive tagging of antibodies and other binding reagents. Researchers generate Cy5-labeled immunostaining reagents to quantify fluorescence intensity by instrument channels optimized for far-red detection, enabling multicolor panels where Cy5 helps distinguish targets from fluorophores in the visible range. This labeling approach is also used during assay development to evaluate reagent performance and staining patterns across experimental conditions.