Azido-PEG5-CH2CO2-NHS | CAS 2144777-77-3

Azido-PEG5-CH2CO2-NHS is a PEG-based heterobifunctional click chemistry reagent that combines an azide handle for bioorthogonal conjugation with an NHS ester for efficient coupling to primary amines. As an azide-functionalized NHS ester, it is widely used to introduce a clickable PEG spacer onto proteins, peptides, and other amine-containing biomolecules, improving solubility and conjugation control while enabling downstream strain-promoted or copper-catalyzed azide–alkyne cycloaddition workflows. The reagent’s flexible PEG5 linker and reactive NHS group make it a practical intermediate for preparing imaging probes, affinity reagents, and modular biomaterials that require orthogonal attachment points.

1. Protein PEGylation And Labeling

Azido-PEG5-CH2CO2-NHS is commonly used to attach a PEG spacer to lysine residues on antibodies, enzymes, and other amine-rich proteins via the NHS ester, generating a defined azide-functional conjugate for subsequent click labeling. Researchers use the resulting azido-PEGylated proteins to improve stability, reduce nonspecific interactions, and create a standardized platform for attaching fluorophores, affinity tags, or biophysical reporters through azide–alkyne cycloaddition. This approach is frequently adopted in molecular imaging reagent development and in quantitative assay workflows where modular labeling is preferred over direct dye-to-protein coupling.

2. Surface And Bead Functionalization

Azido-PEG5-CH2CO2-NHS is well suited for preparing azide-functional surfaces and solid supports by coupling the NHS ester to amine-bearing coatings, resins, or bead chemistries, followed by click-based immobilization of complementary alkyne partners. In diagnostic reagent development and analytical chemistry workflows, azide-functionalized beads enable consistent conjugation of capture ligands, detection handles, or multivalent probe architectures without repeated optimization of labeling conditions. The PEG5 spacer helps maintain accessibility of the azide group at the interface, which is particularly valuable for building robust reagent formats for imaging, binding assays, and multiplexed analytical formats.

3. Bioconjugate Linker For Probes

Azido-PEG5-CH2CO2-NHS is used as a modular linker to generate clickable bioconjugates for fluorescence, luminescence, and affinity-based probe construction. By first installing the azide-bearing PEG handle onto an amine-containing targeting moiety such as a peptide, protein fragment, or polymer, the reagent enables later attachment of diverse reporters or enrichment tags using click chemistry strategies compatible with complex labeling environments. This two-step design supports scalable probe assembly in research laboratories and reagent manufacturing settings, where separating the amine-coupling step from the final reporter attachment improves reproducibility and simplifies inventory of modular components.

4. PEG Spacer For Biomaterials

Azido-PEG5-CH2CO2-NHS is frequently incorporated into biomaterials and hydrogel modification strategies to introduce azide functionality into otherwise non-clickable polymer networks. The NHS ester allows coupling to amine-containing components, enabling subsequent crosslinking or functionalization with alkyne-bearing moieties to tune material properties and create sites for probe attachment. Biomaterials scientists use the PEG5 linker to improve hydration and reduce steric hindrance, supporting more reliable presentation of clickable groups for building functional surfaces, imaging scaffolds, and modular material platforms used in chemical biology and molecular imaging research tool development.