5-Carboxytetramethylrhodamine succinimidyl ester | CAS 150810-68-7

5-Carboxytetramethylrhodamine succinimidyl ester is a reactive rhodamine-based fluorescent dye designed for efficient NHS ester labeling of primary amines. The dye's bright, red/orange fluorescence is widely used to generate covalent fluorescent conjugates for microscopy, flow cytometry, and fluorescence-based assays. Because the succinimidyl ester reacts with lysine residues and N-termini under standard bioconjugation conditions, it is commonly selected when stable amine-reactive labeling is required for protein, peptide, or nucleic-acid-associated constructs.

1. Protein And Antibody Labeling

5-Carboxytetramethylrhodamine succinimidyl ester is frequently used by protein bioconjugation workflows to produce fluorescently labeled antibodies, enzymes, and affinity reagents through covalent attachment to lysine-containing biomolecules. Researchers and assay developers rely on the dye's amine-reactive NHS ester chemistry to create stable rhodamine conjugates for downstream fluorescence imaging and quantitative readouts, including labeling of capture reagents used in immunoassays, binding studies, and fluorescence microscopy of biomolecular interactions.

2. Fluorescence Microscopy Staining

5-Carboxytetramethylrhodamine succinimidyl ester supports fluorescent labeling strategies for cellular and biomaterial imaging where red/orange emission provides strong contrast against common background channels. Imaging groups use the dye to tag proteins on fixed samples, label extracellular matrices, and prepare fluorescent conjugates for immunostaining workflows, leveraging the covalent amine-reactive functionality to retain signal during washing steps typical of microscopy protocols. The resulting rhodamine conjugates are commonly incorporated into multicolor imaging panels when spectral separation from other fluorophores is planned.

3. Flow Cytometry Conjugates

5-Carboxytetramethylrhodamine succinimidyl ester is applied in flow cytometry reagent development to generate fluorescently labeled proteins and antibody conjugates for cell-surface or intracellular staining workflows that require covalent attachment to amine-containing targets. Cytometry users value the NHS ester's ability to produce stable dye loading on lysine-rich biomolecules, enabling consistent staining for fluorescence readout and enabling quantitative comparison across samples. The dye's rhodamine emission profile is often selected to fit standard red fluorescence detection channels in benchtop cytometers.

4. Fluorescent Bioassay Reagents

5-Carboxytetramethylrhodamine succinimidyl ester is used to build fluorescent components for solution-phase and plate-based fluorescence assays, including labeling of assay enzymes, binding proteins, and reporter conjugates used in kinetic or endpoint formats. Assay developers incorporate the dye-labeled biomolecules as fluorescent tracers or detection reagents where covalent labeling helps maintain reagent integrity during incubation and wash steps. The amine-reactive NHS ester functionality supports straightforward preparation of rhodamine-tagged conjugates for fluorescence-based binding and interaction studies.

5. Biomaterial Surface Functionalization

5-Carboxytetramethylrhodamine succinimidyl ester is commonly used in biomaterials and surface chemistry workflows to fluorescently functionalize amine-bearing surfaces and coatings for imaging and material characterization. Researchers employ the NHS ester to attach rhodamine to polymer films, protein-functionalized scaffolds, and other amine-containing substrates, enabling visualization of coating uniformity, spatial distribution, and surface-associated biomolecule localization. This application is particularly relevant when stable covalent dye attachment is needed to withstand repeated washing and handling during microscopy or fluorescence mapping.