APN-C3-PEG4-azide | CAS 2183440-32-4

APN-C3-PEG4-azide is a PEGylated azide-functionalized click chemistry reagent designed for copper-free and bioorthogonal conjugation workflows. As an azide handle, it is commonly used as the complementary partner in strain-promoted azide–alkyne cycloaddition (SPAAC) to install targeting ligands, imaging tags, or functional payloads onto biomolecules and materials. The C3 linker and PEG4 spacer provide aqueous compatibility and help reduce steric congestion, making APN-C3-PEG4-azide a practical building block for creating well-defined conjugates in chemical biology and molecular imaging research.

1. Targeted Probe Conjugation

APN-C3-PEG4-azide is widely used to generate modular, targeting-capable probes by providing a stable azide functional group for subsequent SPAAC coupling. Researchers incorporate this reagent into biomolecule conjugation schemes where PEG spacing improves accessibility of the conjugation site and supports consistent labeling density. Typical downstream products include azide-bearing probe conjugates for receptor-binding studies, affinity reagents, and multi-component sensor constructs used in chemical biology tool development.

2. Molecular Imaging Reagent Building

APN-C3-PEG4-azide serves as a convenient azide precursor for assembling imaging reagents that require orthogonal attachment of fluorophores, luminescent reporters, or other detectable moieties. In molecular imaging workflows, the PEG4 spacer helps maintain solubility and reduces nonspecific interactions during probe preparation and handling. This reagent is commonly selected when researchers need a reliable azide handle to rapidly exchange or multiplex imaging labels while keeping the core targeting or scaffold component constant.

3. Surface And Material Functionalization

APN-C3-PEG4-azide is used in biomaterials science to functionalize surfaces and polymeric materials with click-reactive azide groups that can be addressed by SPAAC partners. The PEG spacer supports favorable interfacial behavior in aqueous processing, which is valuable for coating, patterning, and constructing functional material platforms for assay development. Downstream applications include azide-functional surfaces for immobilizing capture ligands, creating responsive material interfaces, and building modular composite materials with defined functional density.

4. Bioorthogonal Labeling Of Biomolecules

APN-C3-PEG4-azide is commonly applied in bioconjugation workflows to introduce an azide handle onto proteins, peptides, or other biomolecular scaffolds for subsequent bioorthogonal coupling. The C3/PEG4 architecture provides a flexible linkage that can improve labeling uniformity and help preserve biomolecular recognition elements during conjugate construction. This reagent is frequently used by laboratories developing research-grade conjugates for pathway mapping, reagent standardization, and multi-label experimental designs where orthogonality and reproducible attachment are priorities.