Azido-PEG4-nitrile | CAS 2194563-82-9

Azido-PEG4-nitrile is a PEG-based azide functional reagent that combines an azide handle for copper-free or copper-mediated click chemistry with a nitrile group that can serve as a stable, chemically inert substituent for material and probe design. Its short, flexible PEG spacer supports aqueous compatibility and reduces steric constraints during conjugation, making it useful for attaching biomolecular targeting motifs, imaging tags, or polymeric components to azide-reactive partners. As a modular linker, Azido-PEG4-nitrile is commonly selected in workflows that require controlled installation of an azide-bearing PEG spacer for downstream click conjugation and surface or material functionalization.

1. Bioconjugation Linker Use

Azido-PEG4-nitrile is widely used as an azide-bearing PEG linker for preparing click-ready bioconjugates, including conjugation of proteins, peptides, and nucleic-acid–associated constructs to complementary cyclooctyne or strained-alkyne partners. The PEG4 spacer improves solubility and helps maintain accessibility of the reactive handle, which is particularly valuable when labeling complex biomolecules or assembling multicomponent reagents for assay development. Researchers also leverage the nitrile substituent as a chemically robust group that can remain intact during labeling and purification steps, supporting consistent reagent performance across iterative conjugation workflows.

2. Surface And Material Functionalization

Azido-PEG4-nitrile is used to introduce azide functionality onto polymeric surfaces, nanoparticles, and biomaterial scaffolds, enabling subsequent click coupling to surface-bound alkynes or cyclooctyne-functional coatings. The flexible PEG spacer helps mitigate non-specific interactions and supports more uniform presentation of the reactive azide at interfaces, which is important for reproducible surface chemistry in materials research. In practical downstream development, this reagent supports modular fabrication of functional coatings, biointerface layers, and PEGylated material conjugates where the azide handle must be preserved for later patterning or assembly.

3. Molecular Imaging Probe Assembly

Azido-PEG4-nitrile is commonly incorporated into probe-building pipelines where an azide-functional PEG spacer is required to connect imaging moieties to targeting ligands or reporter scaffolds via click chemistry. The PEG4 unit supports water-compatible probe architectures and helps maintain the spatial separation between the imaging label and the recognition element, improving conjugate design flexibility for fluorescent, luminescent, or other tag-based detection platforms. Because the nitrile group is stable under typical labeling and handling conditions, it can be retained as part of the final probe scaffold while the azide handle is reserved for controlled coupling to the appropriate imaging partner.

4. Diagnostic Reagent And Assay Platforms

Azido-PEG4-nitrile is frequently used to prepare azide-functional components for diagnostic reagent development and assay platform assembly, including labeling of assay reagents, immobilizable conjugates, and modular reagent cartridges. The azide handle enables straightforward integration with complementary click partners, allowing teams to swap targeting ligands, reporter groups, or immobilization chemistries without redesigning the entire conjugate. The PEG4 spacer contributes to solubility and reduces steric hindrance during conjugation and subsequent binding steps in assay workflows, supporting consistent reagent handling from synthesis through final formulation.