N-(Azido-PEG3)-N-bis(PEG3-acid) | CAS 2055042-57-2

N-(Azido-PEG3)-N-bis(PEG3-acid) is a PEG-based azide-functionalized click chemistry reagent designed for strain-promoted or copper-catalyzed azide–alkyne cycloaddition workflows in chemical biology and materials science. The molecule combines a terminal azide handle with multiple PEG3 segments and carboxylic acid functionality, enabling aqueous compatibility and convenient downstream coupling or surface immobilization. Its amphiphilic, water-soluble architecture makes it particularly useful for building modular linkers for probe conjugation, biomolecule functionalization, and polymer or nanoparticle surface engineering.

1. Bioconjugation Linkers

N-(Azido-PEG3)-N-bis(PEG3-acid) is widely used as a flexible, water-compatible azide linker to install click handles on proteins, peptides, and other biomolecular scaffolds prior to conjugation with alkyne-bearing partners. The PEG3 spacing helps reduce steric constraints and improves accessibility of the azide during subsequent click coupling steps, which is valuable when preparing multicomponent labeling reagents for cell-surface or intracellular biomolecule studies. Carboxylic acid groups provide additional coordination and coupling options for integrating the conjugate into larger constructs, such as attaching to amine-reactive or metal-coordinating materials during assay or imaging reagent assembly.

2. Surface Functionalization

N-(Azido-PEG3)-N-bis(PEG3-acid) is commonly applied to functionalize material surfaces and colloidal interfaces where azide presentation and aqueous stability are critical. The PEG-rich structure supports uniform dispersion in buffer and can be used to introduce azide termini onto polymer films, hydrogel surfaces, or nanoparticle coatings, enabling subsequent attachment of alkyne-functional ligands, imaging moieties, or affinity tags through click chemistry. Carboxylic acid functionality further supports robust surface integration strategies, including electrostatic interactions and coordination-driven anchoring, which are frequently leveraged in next-generation biosensing and molecular imaging platform development.

3. Molecular Imaging Probes

N-(Azido-PEG3)-N-bis(PEG3-acid) serves as a practical azide-bearing building block for generating modular molecular imaging probes and fluorescent or luminescent conjugates that require controlled linker length and hydrophilicity. Researchers often incorporate this reagent to standardize the distance between a targeting or reporting group and the conjugation point, using the PEG3 segments to mitigate nonspecific interactions and improve probe behavior in aqueous imaging buffers. The presence of carboxylic acid groups also supports compatibility with common probe formulation workflows, including conjugate assembly into multi-ligand imaging constructs where orthogonal chemistry steps are used to assemble complex probe architectures.

4. Diagnostic Reagent Assembly

N-(Azido-PEG3)-N-bis(PEG3-acid) is used in the preparation of diagnostic and research assay reagents that rely on modular, click-based assembly of detection components. The reagent’s azide handle enables efficient coupling to alkyne-functional reporter groups, affinity ligands, or signal transduction elements, supporting reproducible construction of multivalent assay formats such as labeled binding reagents or multiplexed detection panels. PEG3-mediated solubility and spacing are particularly helpful when designing conjugates intended to remain stable in complex assay matrices, while the carboxylic acid functionality supports integration into immobilization and conjugation workflows used to build assay-ready reagent libraries.