Cyanine3B carboxylic acid | CAS 228272-69-3

Cyanine3B carboxylic acid is a cyanine dye bearing a carboxylic acid functional group that enables covalent attachment to amine-containing biomolecules and labeling handles commonly used in fluorescence workflows. Its bright visible emission makes it a widely used fluorophore for fluorescence microscopy, imaging-based assays, and fluorescent conjugate preparation where red-orange signal readout is required. Researchers typically select Cyanine3B carboxylic acid when they need a reactive dye for building fluorescent bioconjugates and standardized staining reagents.

1. Protein Fluorescent Labeling

Cyanine3B carboxylic acid is used to generate fluorescent protein conjugates for imaging and assay development, particularly when a carboxyl-reactive dye format is desired for coupling to lysine-rich targets. Protein labeling workflows in cell biology and chemical biology commonly employ Cyanine3B carboxylic acid to prepare antibody conjugates, enzyme conjugates, and fluorescent standards for downstream microscopy, gel-based readouts, and plate-based fluorescence measurements. The dye's cyanine brightness supports visualization of labeled biomolecules in experimental formats where red-orange fluorescence is advantageous for multiplexing with other channels.

2. Fluorescence Microscopy Staining

Cyanine3B carboxylic acid is frequently incorporated into fluorescent staining reagents for cellular and biomaterial imaging experiments, where covalent tagging of targeting or affinity reagents enables stable signal localization. In fluorescence microscopy workflows, researchers use Cyanine3B carboxylic acid to label biomolecule probes that bind cell-surface markers, extracellular matrices, or assay-specific components, supporting localization studies and qualitative tracking of labeled species. The carboxylic acid functionality supports preparation of dye-conjugated staining constructs that can be integrated into fixed-sample imaging and microscopy-based fluorescence readouts.

3. Oligonucleotide and Probe Conjugates

Cyanine3B carboxylic acid is applied in the construction of fluorescent nucleic-acid reagents and probe conjugates when dye attachment to oligonucleotide scaffolds is required for fluorescence detection. Molecular imaging and nucleic-acid analysis workflows often use cyanine dye labeling to create fluorescent reporters for hybridization-based experiments, complementary-strand tracking, and fluorescence readouts in lab-developed assays. By enabling covalent dye incorporation through its carboxylic acid handle, Cyanine3B carboxylic acid supports the preparation of labeled oligonucleotide probes used in fluorescence-based analytical platforms.

4. Fluorescent Bioassay Reagent Development

Cyanine3B carboxylic acid is used to build fluorescent assay reagents in research settings where a reactive dye is needed to generate labeled components for signal generation. In fluorescence assay development, teams commonly prepare dye-conjugated biomolecules or labeling reagents that serve as readout reporters in binding assays, enzymatic activity formats, and fluorescence-based screening workflows. The dye's visible emission and covalent labeling utility make Cyanine3B carboxylic acid a practical choice for constructing assay conjugates that can be measured on standard fluorescence imaging and plate-reader instrumentation.