mPEG5-azide | CAS 1202681-04-6

mPEG5-azide is a methoxy-terminated polyethylene glycol (PEG) azide reagent designed for bioorthogonal click chemistry workflows. As an azide-functionalized PEG, it serves as a versatile handle for copper-free or copper-mediated azide–alkyne cycloaddition strategies, enabling controlled PEGylation-like modifications of biomolecules, surfaces, and probe constructs. Its short, well-defined PEG chain length supports improved solubility and tunable steric properties, making it a common reagent in chemical biology, materials functionalization, and imaging probe development where PEG incorporation is used to modulate conjugate behavior.

1. PEGylation Of Biomolecules

mPEG5-azide is widely used to introduce a PEG spacer into proteins, peptides, and other biomolecular conjugates via azide–alkyne click coupling to complementary alkyne-bearing partners. Researchers employ this reagent to generate PEG-modified bioconjugates that show improved aqueous handling, reduced nonspecific interactions, and more consistent presentation of functional groups on the conjugate surface. In chemical biology workflows, mPEG5-azide is frequently selected when a compact PEG chain is desired to balance solubility enhancement with minimal changes to molecular recognition or binding-site accessibility.

2. Surface And Material Functionalization

mPEG5-azide supports the preparation of PEG-functional materials by enabling click attachment to alkyne-terminated coatings, beads, or patterned substrates. Surface chemists use the azide handle to graft PEG layers that can suppress fouling, improve wettability, and create controlled interfacial environments for downstream assays and binding studies. This reagent is also used in the development of functionalized hydrogels and polymer surfaces where PEG incorporation helps regulate diffusion and nonspecific adsorption of biomolecules during incubation-based experiments.

3. Imaging Probe And Labeling Platforms

mPEG5-azide is commonly incorporated into molecular imaging and detection reagent pipelines as a PEG linker that improves probe solubility and helps manage background signal in labeling workflows. Probe developers use the azide group to click-connect PEG spacers to alkyne-functional fluorophores, affinity tags, or reporter scaffolds, producing conjugates with more favorable handling characteristics for in vitro assays and microscopy-compatible workflows. The defined PEG5 length is particularly useful when a modest hydrophilic spacer is needed to reduce aggregation without excessively increasing probe size.

4. Diagnostic Reagent Conjugate Building

mPEG5-azide is used as a modular PEG component in the construction of diagnostic and analytical reagent conjugates, including affinity reagent formats and multiplexing-ready labeling constructs. By coupling the azide functionality to alkyne-bearing capture elements, researchers can tune conjugate architecture to improve stability in assay buffers and reduce nonspecific binding to assay plastics or membranes. In reagent development settings, mPEG5-azide is frequently chosen to provide a consistent PEG spacer that supports reproducible conjugation geometry across batches of labeled materials.