N-(Azido-PEG4)-N-bis(PEG4-acid) | CAS 2093152-80-6

N-(Azido-PEG4)-N-bis(PEG4-acid) is a PEG-based azide-functional click chemistry reagent designed for bioconjugation workflows that benefit from water solubility and reduced nonspecific interactions. As an azide handle for copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) and related click strategies, it provides a flexible PEG spacer architecture and two carboxylic acid termini for downstream coupling to activated surfaces, polymers, and biomaterial scaffolds. This combination of an azide reactive group with PEG4-acid functionality makes it well suited for constructing stable, modular conjugates used in chemical biology, imaging reagent development, and materials functionalization.

1. Surface PEGylation

N-(Azido-PEG4)-N-bis(PEG4-acid) is commonly used to introduce an azide-bearing, PEG-rich linker onto surfaces and solid supports where subsequent click attachment of probes, targeting ligands, or reporter groups is required. The bis(PEG4-acid) motif supports robust immobilization strategies through carboxylate-reactive chemistries, while the azide provides a convenient orthogonal handle for later CuAAC conjugation. This architecture is particularly valuable for creating low-fouling, highly hydrated interfaces in research-grade assay platforms and functionalized material coatings.

2. Biomolecule Conjugation Platforms

N-(Azido-PEG4)-N-bis(PEG4-acid) serves as a modular PEG spacer for building conjugation-ready biomolecule platforms, including azide-functional linkers for attaching biomolecular recognition elements to imaging tags or affinity reagents. Researchers often leverage the carboxylic acid functionality to incorporate the reagent into activated carrier systems, then use the azide group to click on alkyne-bearing partners under mild conditions. The PEG4 spacing helps maintain accessibility of the azide for efficient downstream labeling while supporting conjugate solubility in aqueous buffers.

3. Molecular Imaging Probe Assembly

N-(Azido-PEG4)-N-bis(PEG4-acid) is frequently incorporated into molecular imaging probe construction workflows that require controlled, flexible distance between a scaffold and a reactive labeling moiety. The azide enables rapid installation of alkyne-functional fluorophores, affinity reporters, or signal-generating components via click coupling, while the PEG4-acid termini facilitate integration into probe precursors and scaffold materials. This reagent is therefore used to generate consistent probe architectures that support reproducible labeling density and improved handling during probe synthesis and characterization.

4. Hydrogel And Polymer Functionalization

N-(Azido-PEG4)-N-bis(PEG4-acid) is used to functionalize hydrogels and polymeric materials with azide groups that can be subsequently patterned or decorated through click chemistry. The bis(PEG4-acid) functionality supports incorporation into polymer networks or attachment to carboxyl-reactive crosslinking schemes, yielding materials with tunable spacing and reduced steric hindrance for later alkyne-mediated labeling. Such azide-functional polymer platforms are widely adopted in biomaterials research to enable spatially controlled conjugation of fluorescent markers, affinity handles, or other modular components.