N-(azide-PEG3)-N'-(m-PEG4)-Benzothiazole Cy5 | CAS 2107273-88-9

N-(azide-PEG3)-N'-(m-PEG4)-Benzothiazole Cy5 is a Cy5-based fluorescent labeling reagent bearing an azide functional group, designed for attachment to biomolecules and materials through azide-compatible conjugation workflows. The benzothiazole Cy5 scaffold provides strong far-red fluorescence for fluorescence imaging and labeling experiments, while the PEG spacers support reduced steric constraints and improved accessibility of the reactive handle. In practice, this reagent is used to build fluorescent conjugates for cellular and molecular assays where far-red signal separation and PEG-mediated flexibility are advantageous.

1. Biomolecule Labeling

N-(azide-PEG3)-N'-(m-PEG4)-Benzothiazole Cy5 is used by chemical biology and protein engineering groups to generate far-red fluorescent conjugates for tracking biomolecules in solution and on surfaces. Researchers typically incorporate the azide handle into labeling strategies to attach Cy5 to peptides, proteins, antibodies, or other targeting ligands, creating imaging reagents for binding and uptake studies. The PEG3/PEG4 spacers help maintain fluorophore accessibility after conjugation, which is particularly useful when labeling macromolecules with multiple functional sites or when steric crowding can reduce effective labeling density.

2. Fluorescence Microscopy Imaging

N-(azide-PEG3)-N'-(m-PEG4)-Benzothiazole Cy5 supports fluorescence microscopy workflows that benefit from far-red excitation and emission, including multicolor imaging experiments where spectral overlap with green or orange channels is a concern. Cell imaging teams use the reagent as a fluorescent tag within conjugated probes that label extracellular targets, cell-associated biomolecules, or engineered constructs in fixed or prepared samples. The flexible PEG linkers can improve uniform staining of conjugates on complex biological surfaces, helping maintain consistent fluorescence distribution for qualitative localization and comparative imaging across experimental conditions.

3. Flow Cytometry Fluorescent Conjugates

N-(azide-PEG3)-N'-(m-PEG4)-Benzothiazole Cy5 is frequently employed in flow cytometry reagent development to create far-red fluorescent conjugates for quantitative labeling of cells and cell-surface components. Assay developers use the azide-functional Cy5 to assemble fluorescent probes that report on binding events, surface marker engagement, or labeling of engineered biomaterials associated with cells. The PEG spacers can reduce steric hindrance between the fluorophore and the recognition element, supporting robust staining performance in suspension-based measurements where consistent labeling is critical for gating and population analysis.

4. Surface Functionalization Probes

N-(azide-PEG3)-N'-(m-PEG4)-Benzothiazole Cy5 is used in biomaterials and materials chemistry labs to prepare fluorescent surface-functionalization reagents for imaging and characterization of modified substrates. Researchers incorporate the azide-bearing Cy5 into labeling schemes for attaching fluorescence to polymer films, hydrogels, or nanoparticle surfaces, enabling visualization of coating uniformity, surface coverage, and spatial distribution in microscopy-based readouts. The PEG linkers help maintain fluorophore exposure away from the surface, which is useful when characterizing heterogeneous materials where signal attenuation from close surface proximity can otherwise complicate interpretation.