Cyanine3.5 NHS ester | CAS 2231670-85-0

Cyanine3.5 NHS ester is a reactive cyanine dye designed for covalent fluorescent labeling via NHS-ester chemistry, enabling attachment to primary amines on proteins, peptides, and other amine-containing biomolecules. Its cyanine chromophore provides strong fluorescence for fluorescence microscopy and fluorescence-based readouts, and the NHS ester format supports straightforward conjugate preparation for imaging and assay development workflows.

1. Protein Fluorescent Labeling

Cyanine3.5 NHS ester is frequently used by protein bioconjugation teams to generate fluorescently labeled antibodies, enzymes, and protein standards for imaging and binding studies. Researchers typically incorporate the dye into amine-containing proteins to create stable conjugates for fluorescence microscopy and fluorescence-based assays, where the labeling density can be tuned through reaction stoichiometry to balance brightness and functional retention. This reagent format is also commonly selected for preparing labeled controls used in assay optimization, co-localization experiments, and fluorescence quantification workflows.

2. Fluorescence Microscopy Staining

Cyanine3.5 NHS ester supports fluorescence microscopy staining of fixed or permeabilized biological samples when amine-bearing targets are accessible to covalent labeling. Imaging groups use the dye-conjugated biomolecules to visualize cellular structures and biomolecular distributions, including labeled affinity reagents used for immunofluorescence-like workflows in research settings. The cyanine dye's emission in the red-orange region makes it a practical choice for multicolor imaging strategies where spectral separation from common green fluorophores is required, provided the imaging system is configured to the dye's excitation and emission bands.

3. Flow Cytometry Conjugate Preparation

Cyanine3.5 NHS ester is used in flow cytometry reagent development to prepare fluorescent labeling reagents for quantifying biomolecule abundance on beads or cell-associated targets after appropriate conjugate handling. Assay developers often label amine-containing proteins used as detection reagents, enabling fluorescence readout in instrumentation configured for cyanine dye channels. This labeling approach is also used to generate calibration materials and fluorescent standards for method development, gating strategy refinement, and reproducible signal generation across experimental runs.

4. Fluorescent Bioassay Reagent Development

Cyanine3.5 NHS ester is widely applied in fluorescence assay development to produce labeled reagents for binding assays, reporter conjugates, and fluorescence-based detection formats. Biochemical assay teams use cyanine-labeled biomolecules as fluorescent tracers to monitor interactions and process outcomes in plate-based workflows, where consistent labeling provides stable signal generation. The NHS-ester chemistry enables conjugate construction with amine-functionalized assay components, supporting assay prototyping for research screening and characterization of biomolecular systems.