Sulfo-Cyanine3 NHS Ester (ethyl) potassium salt (1:1) | CAS 945529-56-6

Sulfo-Cyanine3 NHS Ester (ethyl) potassium salt (1:1) is a water-soluble, sulfonated cyanine dye designed for NHS-ester bioconjugation to primary amines on proteins, peptides, and other carrier biomolecules. Its Cy3-class emission supports bright visible fluorescence for labeling workflows used in fluorescence microscopy, quantitative fluorescence assays, and imaging reagent development. The dye's sulfonate functionality helps maintain aqueous compatibility for conjugate preparation and downstream handling.

1. Protein And Antibody Labeling

Sulfo-Cyanine3 NHS Ester (ethyl) potassium salt (1:1) is widely used by protein chemistry and chemical biology groups to generate Cy3-labeled antibodies, antibody fragments, enzyme conjugates, and affinity reagents for fluorescence-based detection. The NHS-ester reactivity enables straightforward attachment to lysine residues and N-termini, producing fluorescent conjugates that can be used as imaging reagents for binding studies, target localization experiments, and assay reagent development where a Cy3-like spectral channel is appropriate. Researchers also rely on the sulfonated, water-soluble dye format to support conjugation in aqueous buffers and to reduce handling issues associated with more hydrophobic cyanines.

2. Fluorescence Microscopy Staining

Sulfo-Cyanine3 NHS Ester (ethyl) potassium salt (1:1) supports fluorescence microscopy workflows where labeled biomolecules are used as probes for cellular and molecular imaging. Common uses include preparing Cy3-conjugated secondary reagents, labeling extracellular targets, and generating fluorescent tracers for imaging experiments that require a bright, visible-range cyanine signal. Because the dye is installed via amine-reactive NHS chemistry, it is frequently incorporated into labeling strategies for fixed-cell or fixed-sample imaging, including immunofluorescence-style experiments and fluorescence localization studies in microscopy platforms that detect Cy3 emission.

3. Flow Cytometry Conjugate Preparation

Sulfo-Cyanine3 NHS Ester (ethyl) potassium salt (1:1) is used in flow cytometry reagent development to produce Cy3-labeled biomolecules for fluorescence readout in cell-surface and biomarker labeling experiments. Researchers generate fluorescent conjugates by coupling the NHS ester to amine-containing targeting proteins, such as antibodies or binding ligands, to create reagents compatible with standard flow cytometers equipped with appropriate excitation/emission detection channels for Cy3. The sulfonated dye format helps maintain aqueous compatibility during conjugate preparation and storage, supporting consistent staining workflows for quantitative fluorescence measurements.

4. Fluorescent Bioassay Reagent Development

Sulfo-Cyanine3 NHS Ester (ethyl) potassium salt (1:1) is frequently incorporated into fluorescence assay development where an amine-reactive fluorescent tag is needed to build labeled assay components. Typical applications include preparing fluorescently labeled assay standards, labeling proteins used in binding assays, and constructing fluorescent detection reagents for plate-based readouts. The dye's Cy3-class emission is commonly leveraged in multiplex-friendly assay designs where visible fluorescence channels are already established, enabling researchers to track binding or reagent distribution using fluorescence intensity measurements on common microplate readers and imaging-capable assay platforms.