Azido-PEG1-methyl ester | CAS 1835759-80-2

Azido-PEG1-methyl ester is a short-chain azide-functionalized polyethylene glycol (PEG) methyl ester designed for bioorthogonal click chemistry workflows, most commonly in strain-promoted or copper-catalyzed azide–alkyne cycloaddition formats. Its compact PEG spacer and activated methyl ester handle make it well suited for introducing an azide “handle” while enabling downstream conjugation strategies that rely on ester reactivity or subsequent functional group interconversion. In research and materials settings, this reagent is frequently used to build modular PEGylated constructs for controlled solubility, surface presentation, and labeling of biomolecules and biomaterial interfaces.

1. Biomolecule PEGylation

Azido-PEG1-methyl ester is used to incorporate a PEG spacer onto proteins, peptides, and other biomolecular scaffolds where improved aqueous handling and reduced non-specific interactions are desired for labeling or analytical workflows. The azide functionality provides a reliable click handle for attaching fluorophores, affinity tags, or other reporter groups through azide–alkyne conjugation, while the methyl ester offers an additional site for chemical derivatization routes that can be leveraged during construct assembly. Researchers commonly employ this reagent when they need a compact PEG length that preserves molecular recognition while still providing practical improvements in solubility and conjugate stability.

2. Surface And Interface Labeling

Azido-PEG1-methyl ester is well matched for modifying material surfaces and engineered interfaces that require spatially controlled PEG spacing prior to click-based attachment of probes. The azide group enables post-functionalization using complementary clickable partners, allowing sequential build-up of functional coatings, sensor surfaces, or patterned materials without requiring harsh conditions at every step. The short PEG1 spacer helps tune interfacial accessibility and reduces steric congestion compared with longer linkers, which can be advantageous when immobilizing small imaging or affinity ligands onto surfaces for downstream characterization.

3. Molecular Imaging Probe Building

Azido-PEG1-methyl ester is frequently used as a modular precursor for constructing imaging and detection probes that rely on click chemistry for rapid, high-specificity conjugation. By installing an azide-bearing PEG handle onto a targeting scaffold or a reporter moiety, teams can later couple the construct to alkyne-functional dyes, affinity reagents, or imaging tags under standardized click conditions. The methyl ester component also supports intermediate derivatization steps during probe assembly, helping developers manage solubility and handleability during reagent preparation and characterization.

4. Diagnostic Reagent Conjugates

Azido-PEG1-methyl ester is used in the development of laboratory diagnostic and assay reagents where consistent conjugation chemistry and modular assembly are important. The azide functionality supports orthogonal coupling to complementary clickable components, enabling rapid generation of reagent conjugates such as enzyme-linked, affinity-based, or fluorescence-labeled assay materials. Short PEG spacing can be particularly useful in assay contexts where minimizing linker length improves effective presentation of recognition elements while maintaining sufficient aqueous compatibility for reproducible reagent handling.