Aminooxy-PEG4-azide | CAS 2100306-61-2

Aminooxy-PEG4-azide is a PEG-based bifunctional click chemistry reagent that combines an aminooxy handle with an azide for bioorthogonal conjugation. As an azide-bearing partner, it is commonly used in strain-promoted or copper-catalyzed azide–alkyne cycloaddition workflows to install azide-reactive labels onto biomolecules, surfaces, and polymeric materials. The aminooxy functionality further supports orthogonal oxime ligation strategies, enabling modular assembly of multi-component constructs in chemical biology and materials research.

1. Bioorthogonal Labeling

Aminooxy-PEG4-azide is widely used as a flexible azide-bearing linker for attaching fluorescent dyes, affinity tags, and imaging probes to proteins, peptides, and other targeting ligands. The PEG4 spacer helps reduce steric constraints during subsequent conjugation steps, which is particularly useful when preparing labeled biomolecular reagents for assays and visualization workflows. Researchers often choose this reagent when they need an azide functionality for click-based installation while retaining an additional reactive handle for orthogonal assembly in the same overall labeling pipeline.

2. Surface And Material Functionalization

Aminooxy-PEG4-azide supports the preparation of functionalized biomaterials and engineered surfaces where azide groups are required for downstream click conjugation. It is commonly incorporated into coating strategies, hydrogel modification, and polymer functionalization to create attachment points for subsequent immobilization of biomolecules, nanoparticles, or capture reagents. The PEG4 segment improves accessibility of the azide for reaction with complementary click partners, which helps maintain reactivity after immobilization and supports reproducible surface chemistry for research-grade materials.

3. Multi-Step Bioconjugation Platforms

Aminooxy-PEG4-azide is used in modular bioconjugation schemes that benefit from orthogonal chemistries, pairing an azide for click coupling with an aminooxy group for oxime-based linkage strategies. This dual functionality makes it attractive for building complex conjugates such as multi-labeled probes, branched constructs, and reagent assemblies that require sequential installation of different components. Chemical biology teams frequently rely on this reagent to streamline workflows where one handle is reserved for click installation while the other enables controlled coupling to a separate molecular partner.

4. Molecular Imaging Reagent Building

Aminooxy-PEG4-azide is commonly selected as an intermediate for constructing imaging and detection reagents that require azide-enabled attachment to targeting scaffolds or reporter moieties. By incorporating PEG4 spacing, the reagent helps maintain effective presentation of the azide for conjugation to alkyne-functional imaging components, including fluorogenic labels and signal-generating reporters used in research imaging contexts. The aminooxy functionality further supports orthogonal assembly, enabling investigators to tailor probe architecture for labeling strategies that require more than one chemical handle.