Azido-PEG3-acid | CAS 1056024-94-2

Azido-PEG3-acid is a PEG-based azide-functionalized building block designed for copper-free and copper-mediated click chemistry workflows, enabling efficient conjugation of azide handles to complementary cyclooctyne or alkyne partners. The short PEG3 spacer and terminal carboxylic acid provide both colloidal compatibility and a convenient handle for downstream coupling, making this reagent widely used in chemical biology, probe development, and biomaterials functionalization. Its compact, water-compatible structure supports modular assembly of labeled biomolecules, surface coatings, and imaging reagents where a stable azide moiety is required.

1. Biomolecule Labeling

Azido-PEG3-acid is commonly used as an azide-bearing linker for site-specific or modular modification of proteins, peptides, and nucleic-acid constructs in chemical biology laboratories. Researchers incorporate the azide handle to create versatile intermediate materials that can be clicked to fluorophores, affinity tags, or reporter groups bearing complementary alkyne or cyclooctyne functionalities. The PEG3 spacer helps maintain solubility and reduces steric constraints during conjugation, while the carboxylic acid enables additional coupling steps to surfaces or carrier platforms when a dual-functional linker is advantageous.

2. Surface and Hydrogel Functionalization

Azido-PEG3-acid is frequently selected for introducing azide functionality onto polymeric materials, coatings, and hydrogel matrices used in biomaterials research. The carboxylic acid group supports attachment strategies to activated surfaces or polymer backbones, after which the azide handle is used for subsequent click-based grafting of bioactive ligands, imaging tags, or cell-interaction motifs. This approach is widely used to build modular material libraries where the same azide-functional substrate can be rapidly diversified by clicking with different alkyne/cyclooctyne reagents under conditions compatible with sensitive components.

3. Molecular Imaging Probe Assembly

Azido-PEG3-acid serves as a practical azide component for assembling imaging probes and detection reagents in fluorescence and related labeling workflows. Probe developers use the reagent to install an azide functionality onto targeting scaffolds or scaffold-like carriers, enabling rapid late-stage conjugation to dyes, quencher units, or other reporter groups via click chemistry. The PEG3 chain supports aqueous handling and can help preserve probe responsiveness by improving accessibility of the azide group during conjugation and subsequent labeling steps.

4. Diagnostic Reagent Conjugation

Azido-PEG3-acid is used to prepare azide-functional conjugates that can be coupled to diagnostic assay components, including affinity reagents, capture molecules, and signal-generating labels. In reagent development settings, the azide handle provides a standardized attachment point that supports consistent downstream clicking to complementary partners such as alkyne-tagged reporters or cyclooctyne-functional assay reagents. The terminal carboxylic acid allows integration into linker architectures used for immobilization on assay formats, enabling scalable workflows for constructing multi-component detection systems.