Azido-PEG24-acid | CAS 1167275-20-3

Azido-PEG24-acid is a PEG-based azide functional building block designed for copper-free and copper-mediated click chemistry workflows, where the terminal azide enables robust conjugation to complementary alkyne-bearing partners. The long, flexible PEG spacer and carboxylic acid handle support aqueous compatibility, reduced nonspecific interactions, and straightforward incorporation into bioconjugation and materials assembly pipelines. This structure is widely used to introduce clickable handles into probes, surface coatings, and polymeric constructs for downstream labeling, immobilization, and modular assembly.

1. Bioconjugation Linker Use

Azido-PEG24-acid is commonly used as a PEGylated azide linker to install a click-ready functional group on biomolecule conjugates, including proteins, peptides, and nucleic-acid reagents, where the PEG spacer helps maintain solubility and accessibility of the reactive handle. Researchers select this reagent when they need a carboxylic acid for coupling to amine- or hydrazide-functional platforms, followed by azide–alkyne ligation to attach fluorophores, affinity tags, or other imaging/assay components. The reagent’s extended PEG length is particularly useful when the target partner is sterically demanding or when minimizing aggregation and surface adsorption is important for consistent labeling performance.

2. Molecular Imaging Probe Assembly

Azido-PEG24-acid serves as a practical handle for constructing modular molecular imaging probes by enabling late-stage attachment of imaging moieties through click chemistry. Probe developers often use the carboxylic acid functionality to incorporate the PEG-azide into probe scaffolds or to anchor it to carrier systems, then use azide–alkyne coupling to append dyes, reporter groups, or imaging-compatible ligands. The PEG24 spacer supports dispersibility in aqueous labeling buffers and can improve the effective presentation of the clickable azide relative to shorter linkers, which is advantageous when building multicomponent imaging reagents for microscopy, fluorescence-based assays, or other optical readouts.

3. Surface Functionalization And Coatings

Azido-PEG24-acid is widely applied to introduce clickable chemistry onto material surfaces and device-relevant coatings, leveraging the carboxylic acid for immobilization onto activated substrates and the azide group for subsequent attachment of alkyne-functional ligands. Biomaterials and interface-focused research groups use this reagent to create bioactive or assay-compatible surfaces where PEG spacing reduces nonspecific binding and improves ligand accessibility. After surface installation, azide–alkyne click conjugation enables patterned or modular assembly of capture ligands, fluorescent reporters, and affinity reagents, supporting reproducible surface chemistry for analytical platforms and research-grade diagnostic workflows.

4. Polymer and Nanomaterial Labeling

Azido-PEG24-acid is frequently used to functionalize polymers, nanoparticles, and nanocarriers with azide groups that can be coupled to alkyne-bearing reporters or targeting motifs. Materials scientists choose this reagent when they need a hydrophilic spacer that helps maintain colloidal stability and provides a flexible tether for efficient conjugation. The carboxylic acid handle supports incorporation into polymer backbones or surface-modified particles, and the azide enables orthogonal, modular post-functionalization via click chemistry. This approach is common in the development of research tools such as fluorescently labeled polymers, clickable nanocarriers for assay development, and multivalent constructs where controlled spacing between components is critical.