N-(m-PEG4)-N'-(azide-PEG4)-Cy3 | CAS 2107273-38-9

N-(m-PEG4)-N'-(azide-PEG4)-Cy3 is a Cy3-based fluorescent labeling reagent bearing orthogonal PEG linkers and a terminal azide handle, enabling strain-promoted or copper-catalyzed click conjugation workflows to introduce the Cy3 fluorophore onto amine- or cyclooctyne-functionalized biomolecules, polymers, and surfaces. The Cy3 dye provides bright visible fluorescence for imaging and assay readouts, while the PEG spacers help maintain conjugate solubility and reduce nonspecific interactions during labeling.

1. Biomolecule Labeling

N-(m-PEG4)-N'-(azide-PEG4)-Cy3 is used in bioconjugation workflows to fluorescently tag proteins, peptides, and other biomacromolecules after installing a complementary click partner (commonly cyclooctyne-functional groups) on the target. Researchers employ the azide-functional Cy3 reagent to generate fluorescent conjugates for tracking binding, monitoring assembly of biomolecular complexes, and visualizing labeled components in microscopy-based studies. The PEG spacers are particularly helpful when labeling large or partially hydrophilic biomolecules, supporting consistent labeling performance in aqueous buffers used for biological assays.

2. Click-Constructed Fluorescent Probes

N-(m-PEG4)-N'-(azide-PEG4)-Cy3 is frequently incorporated into fluorescent probe construction where the Cy3 fluorophore is appended to a recognition scaffold via click chemistry. In chemical biology and materials-focused probe development, the azide handle allows modular assembly of probe conjugates by reacting with pre-functionalized targeting motifs, linkers, or carrier platforms bearing a click-reactive complement. This approach is commonly used to generate imaging reagents for fluorescence microscopy readouts, including multicomponent probe libraries where the Cy3 label is introduced as a standardized fluorescent module.

3. Surface And Polymer Functionalization

N-(m-PEG4)-N'-(azide-PEG4)-Cy3 supports fluorescent surface engineering and polymer labeling by enabling covalent attachment of Cy3 to azide-compatible or click-complementary materials. Researchers use the reagent to prepare fluorescently traceable coatings, hydrogels, and polymer conjugates for studying material distribution, diffusion, and cell-material interactions in imaging experiments. The PEG linkers help the Cy3 label remain accessible on the material surface, supporting reliable fluorescence visualization during wash-intensive workflows and time-course microscopy studies.

4. Fluorescence Imaging Standards

N-(m-PEG4)-N'-(azide-PEG4)-Cy3 is also used as a convenient fluorescent labeling building block to prepare calibration and reference conjugates for imaging workflows that rely on Cy3 emission. In microscopy and fluorescence-based assay development, laboratories often generate reproducible Cy3-labeled reference constructs by click-assembling the azide Cy3 reagent with defined complementary partners. These standards help support consistent visualization across experiments, especially when comparing labeled samples, optimizing labeling conditions, or validating imaging setups that detect Cy3 fluorescence.