N-(m-PEG4)-N'-(DBCO-PEG4)-Cy5 | CAS 2107273-76-5

N-(m-PEG4)-N'-(DBCO-PEG4)-Cy5 is a Cy5-based fluorescent click conjugate that combines a DBCO cyclooctyne handle for strain-promoted azide-alkyne cycloaddition (SPAAC) with PEG spacers that improve bioconjugation performance and reduce steric effects. The Cy5 fluorophore enables fluorescence tracking of the labeled biomolecule, while the PEG architecture supports aqueous workflows used in chemical biology, imaging reagent development, and biomaterials surface engineering.

1. Biomolecule Labeling

N-(m-PEG4)-N'-(DBCO-PEG4)-Cy5 is used to fluorescently tag azide-functionalized proteins, peptides, and other biomolecules through SPAAC, enabling direct visualization of conjugation products without requiring copper catalysts. Researchers commonly employ this reagent when they need a Cy5 readout to monitor labeling efficiency, track conjugate distribution in complex mixtures, or confirm successful attachment in downstream assays. The PEG linkers help maintain accessibility of both the DBCO reactive group and the Cy5 dye, which is particularly useful for labeling bulky targets such as antibodies, enzyme conjugates, or multivalent affinity reagents.

2. Fluorescence Imaging Conjugates

N-(m-PEG4)-N'-(DBCO-PEG4)-Cy5 supports fluorescence microscopy workflows where the click-installed Cy5 label is used to localize and follow biomolecular constructs in cells or in biomaterial-associated environments. Chemical biology teams use the DBCO functionality to attach the Cy5 tag to azide-bearing targeting ligands or surface-presenting biomolecules, then image the resulting conjugates to study trafficking, binding to engineered surfaces, or spatial organization of labeled components. The PEG spacers are also beneficial for reducing nonspecific interactions and maintaining consistent labeling behavior in aqueous imaging buffers.

3. Surface Functionalization Click Probes

N-(m-PEG4)-N'-(DBCO-PEG4)-Cy5 is frequently incorporated into material and surface modification strategies where azide-functional groups are presented on nanoparticles, hydrogels, or engineered surfaces, allowing Cy5-tagged constructs to be installed via SPAAC. Biomaterials researchers use the Cy5 signal to quantify surface coverage, visualize coating uniformity, or verify functionalization after immobilization steps. This approach is especially useful for building fluorescently traceable materials for microscopy-based characterization, reagent development for surface-binding studies, and quality control of click-functionalized platforms.