Azide-PEG2-Ms | CAS 176520-23-3

Azide-PEG2-Ms is a heterobifunctional click chemistry reagent combining an azide handle with a methanesulfonate leaving group (Ms) connected through a short polyethylene glycol (PEG2) spacer. As a click-compatible azide, it is commonly used as a versatile functional group for copper-catalyzed azide–alkyne cycloaddition (CuAAC) and related azide-based labeling workflows. The PEG2 linker improves aqueous handling and spacing between biomolecules or material surfaces, while the Ms group enables subsequent attachment strategies that support downstream conjugation, surface functionalization, and probe assembly in chemical biology and biomaterials research.

1. Biomolecule PEGylation

Azide-PEG2-Ms is frequently selected for constructing PEG-modified biomolecule conjugates where a defined azide functionality is required later for orthogonal click labeling. Researchers use the reagent to introduce an azide-bearing PEG spacer onto proteins, peptides, or other functional biomolecules that already contain suitable nucleophilic sites for Ms-mediated coupling, enabling subsequent CuAAC attachment of fluorophores, affinity tags, or imaging handles without redesigning the initial conjugation chemistry. The PEG2 segment helps maintain solubility and reduces steric crowding around the azide, which is advantageous when preparing multi-component labeling reagents for assay development and molecular imaging toolkits.

2. Surface Functionalization for Imaging

Azide-PEG2-Ms is widely used to functionalize material surfaces and interfaces with azide groups for later attachment of imaging probes and diagnostic reagents via click chemistry. In biomaterials and molecular imaging workflows, the Ms leaving group supports covalent incorporation of the PEG2-azide motif onto surfaces that present reactive nucleophiles, providing stable, water-compatible spacing for subsequent CuAAC coupling of dyes, nanoparticles, or targeting ligands. This approach is commonly adopted in research settings where modular probe exchange is needed, allowing teams to generate a library of surface-bound imaging constructs from a single azide-functionalized platform.

3. Affinity Tag and Probe Assembly

Azide-PEG2-Ms serves as a practical building block for assembling affinity-tagged reagents and modular detection probes that require an azide handle for reliable click attachment. Chemical biology groups use Azide-PEG2-Ms to install a PEG2-azide motif onto capture molecules, scaffolds, or linker intermediates, then perform CuAAC to append reporters such as fluorescent dyes, biotin analogs, or other small-molecule tags used in binding assays and analytical workflows. The reagent’s short PEG spacer supports consistent conjugation spacing, improving accessibility of the azide for subsequent labeling steps and helping maintain performance of multi-step probe construction pipelines.

4. Multicomponent Conjugate Libraries

Azide-PEG2-Ms is commonly incorporated into workflows that generate multicomponent conjugate libraries for screening and method development in chemical biology and materials chemistry. By providing an azide-functional PEG handle introduced through Ms-based coupling to a primary scaffold, the reagent enables later diversification through click reactions, supporting rapid exchange of secondary components such as labels, enrichment handles, or reporter moieties. This strategy is particularly useful for teams building panels of conjugates where a standardized azide-bearing intermediate streamlines downstream assembly and reduces variability between probe formats, while the PEG2 linker helps maintain aqueous compatibility across different conjugate architectures.