Azido-PEG3-acetic acid | CAS 172531-37-2

Azido-PEG3-acetic acid is a PEG-based azide building block designed for copper-free and copper-mediated click chemistry workflows, most commonly serving as an azide partner in strain-promoted or CuAAC bioconjugation strategies. Its short, flexible PEG spacer coupled to a terminal azide and carboxylic acid enables straightforward incorporation into hydrophilic linkers, surface coatings, and labeling reagents while improving solubility and reducing nonspecific interactions. This reagent is widely used in research settings to prepare azide-functional handles for subsequent conjugation to alkynes, including in probe, biomaterials, and imaging-platform development.

1. Protein And Peptide Labeling

Azido-PEG3-acetic acid is frequently used to install an azide-functional linker onto proteins and peptides for downstream click conjugation to alkyne-bearing dyes, affinity tags, or imaging handles. The PEG3 spacer helps maintain accessibility of the azide group and supports aqueous compatibility during labeling workflows, which is valuable when preparing multicomponent bioconjugates. Researchers commonly use the carboxylic acid functionality to enable coupling to amine-reactive partners or to incorporate the azide handle into larger linker architectures used for fluorescence labeling, pull-down reagents, or modular probe construction.

2. Biomaterials Surface Functionalization

Azido-PEG3-acetic acid is well suited for introducing azide groups onto biomaterial surfaces and polymeric scaffolds, enabling subsequent attachment of alkyne-functional coatings, bioactive ligands, or crosslinking components via click chemistry. The PEG spacer provides a hydrated interface that can improve presentation of reactive groups and reduce steric hindrance, which is important for reproducible surface conjugation. This reagent is commonly selected for preparing functionalized hydrogels, membrane coatings, and resin or bead-based platforms where azide density and linker flexibility influence the uniformity of downstream attachment.

3. Molecular Imaging Probe Assembly

Azido-PEG3-acetic acid is used as an azide handle in the assembly of molecular imaging probes, where modular click conjugation allows rapid exchange of targeting motifs, reporters, and solubilizing groups. The PEG3-acetic acid motif supports incorporation into probe scaffolds that require aqueous stability and controlled linker length between the azide and the eventual reporter moiety. Imaging-focused research groups often rely on this reagent to standardize azide-functional intermediate materials, streamlining workflows for producing libraries of alkyne-reactive probe conjugates for fluorescence and other labeling modalities.

4. Diagnostic And Assay Reagent Construction

Azido-PEG3-acetic acid supports the construction of diagnostic and assay reagents that require reliable, orthogonal conjugation chemistry to assemble multivalent detection formats. By providing a terminal azide group separated by a short PEG spacer, it enables efficient coupling to alkyne-functional reporters such as enzyme labels, fluorophores, or signal-amplifying components used in assay development. Many reagent developers use azide-functional intermediates like Azido-PEG3-acetic acid to build standardized conjugate building blocks, facilitating consistent manufacturing of detection reagents for research and industrial assay platforms.