Azido-PEG1-CH2CO2-NHS | CAS 1480545-09-2

Azido-PEG1-CH2CO2-NHS is a PEG-based heterobifunctional linker that combines an azide handle for copper-free or copper-mediated click chemistry with an NHS ester for efficient amide coupling to primary amines on proteins, peptides, and other amine-bearing biomolecules. The short PEG spacer and carboxymethyl NHS functionality make it well-suited for preparing defined conjugates where a subsequent click step is used to install fluorophores, affinity tags, or imaging/assay moieties. This reagent is commonly used in chemical biology workflows that require modular assembly of bioconjugates with controlled spacing and minimal perturbation of the target biomolecule.

1. Protein Labeling Workflows

Azido-PEG1-CH2CO2-NHS is widely used to functionalize proteins and peptides by NHS-ester coupling to lysine residues or N-terminal amines, creating an azide-bearing conjugate that can be carried forward into downstream click reactions. Researchers use the azide handle to attach imaging dyes, affinity ligands, or polymeric tags while maintaining a relatively compact PEG spacing that can help preserve binding or activity in sensitive labeling contexts. This approach is particularly common in probe development for microscopy, flow-based assays, and analytical characterization where orthogonal conjugation steps are preferred.

2. Antibody and Affinity Conjugation

Azido-PEG1-CH2CO2-NHS supports azide installation on antibody fragments, antibody conjugates, and other affinity reagents that contain accessible primary amines. By first introducing the azide via NHS coupling, teams can later perform click-based attachment of secondary reporters such as fluorophores, biotin analogs, or solid-support-compatible tags, enabling consistent multistep assembly of labeled binders. The PEG1 spacer helps reduce steric congestion around the azide, which is beneficial when preparing conjugates intended for robust surface binding, signal generation, or standardized reagent panels.

3. Surface Immobilization and Materials

Azido-PEG1-CH2CO2-NHS is used to create azide-functional biomaterials and surface coatings by coupling the NHS ester to amine-terminated surfaces, resins, or polymer matrices, followed by click-based immobilization of complementary partners. This workflow is common in the preparation of affinity surfaces for purification, microarray platforms, and sensor interfaces where modular attachment chemistry improves reproducibility across batches. The resulting azide density and spacing can be tuned by the conjugation conditions, which is valuable for optimizing capture efficiency of immobilized ligands or for building multilayer materials via sequential click steps.

4. Molecular Imaging Probe Assembly

Azido-PEG1-CH2CO2-NHS is frequently employed as a key intermediate for constructing azide-functional imaging probes, where the NHS ester enables rapid incorporation onto amine-bearing targeting scaffolds and the azide subsequently serves as the click-reactive handle. Probe developers use this strategy to assemble conjugates with defined attachment points to dyes, reporter groups, or imaging-compatible moieties, supporting modular optimization of labeling density and linker accessibility. The PEG1 chain provides a practical balance between conjugation efficiency and spatial separation, which can be important for maintaining probe readability in fluorescence-based imaging and analytical detection formats.