N-PEG3-N'-(azide-PEG3)-Cy5 | CAS 2226235-96-5

N-PEG3-N'-(azide-PEG3)-Cy5 is a PEGylated Cy5 labeling reagent bearing two terminal azide groups, enabling modular click chemistry workflows for attaching Cy5 to biomolecules, peptides, and polymer or hydrogel platforms. The Cy5 fluorophore provides far-red fluorescence for imaging and assay development, while the azide handles support copper-catalyzed or strain-promoted azide-alkyne cycloaddition strategies to build defined conjugates with controlled spacing and improved solubility.

1. Biomolecule Fluorescent Labeling

N-PEG3-N'-(azide-PEG3)-Cy5 is used by chemical biology and proteomics groups to generate far-red fluorescent conjugates for microscopy and fluorescence-based binding studies. Researchers typically incorporate the reagent into labeling pipelines where an azide-functional Cy5 construct is clicked onto alkyne-bearing targeting ligands, peptides, or affinity reagents, allowing post-labeling modularity and consistent fluorophore loading. The PEG spacers help reduce steric crowding around the dye, which is helpful when visualizing conjugates in complex biological mixtures such as cell lysates, purified protein assemblies, or affinity-purified biomolecules.

2. Surface And Hydrogel Functionalization

N-PEG3-N'-(azide-PEG3)-Cy5 is applied in biomaterials research to fluorescently tag surfaces, nanoparticles, and hydrogel matrices through azide-alkyne click attachment to alkyne-functional coatings. Materials scientists use the reagent to create stable fluorescent readouts for coating uniformity, material distribution, and transport studies, including visualization of labeled biomaterial domains in microscopy experiments. The PEGylated architecture supports better dispersion and reduced nonspecific dye aggregation compared with more hydrophobic dye conjugates, which is advantageous for reproducible surface patterning and imaging of engineered materials.

3. Multivalent Probe Construction

N-PEG3-N'-(azide-PEG3)-Cy5 is leveraged in fluorescent probe development where multivalency and controlled conjugation geometry are important. Because the molecule carries two azide termini, it can be used as a Cy5 "clickable" building block to assemble dual-labeled constructs, crosslinked imaging scaffolds, or multicomponent probe architectures by sequential or orthogonal coupling to alkyne-functional partners. This approach is particularly useful in FRET-pair design workflows or multiplex imaging reagent development, where defined dye placement and spacing can improve interpretability of fluorescence readouts in microscopy and plate-based assays.

4. Flow Cytometry And Imaging Standards

N-PEG3-N'-(azide-PEG3)-Cy5 supports fluorescence labeling strategies used in cell analysis workflows where far-red channel compatibility is required. Researchers employ the azide-functional Cy5 reagent to prepare fluorescently tagged reagents for instrument calibration, staining controls, and imaging reference standards by clicking the dye onto alkyne-bearing labeling reagents used in cell-surface or biomolecule staining protocols. The PEGylated Cy5 format helps maintain consistent dye behavior during conjugate preparation, supporting reproducible staining intensity across experimental batches for microscopy comparison and flow cytometry gating workflows.