Azido-PEG4-alcohol | CAS 86770-67-4

Azido-PEG4-alcohol is a PEG-based azide building block designed for copper-free or copper-mediated azide–alkyne cycloaddition workflows in chemical biology and materials chemistry. The reagent combines a terminal azide handle with a short, flexible PEG4 spacer terminating in a hydroxyl group, enabling solubility control and straightforward downstream functionalization of biomolecule- or surface-conjugates. Its small, non-ionic polymer segment is commonly used to introduce bioorthogonal labeling sites, improve conjugate handling, and prepare PEGylated linkers for probe and material assembly.

1. Bioorthogonal Labeling Linkers

Azido-PEG4-alcohol is widely used as a linker component for installing azide functionality on surfaces, polymers, and small-molecule scaffolds that later undergo click conjugation with strained alkynes or terminal alkynes. Researchers in chemical biology and proteomics workflows often select PEG4 spacers to reduce steric congestion around the reactive handle and to improve aqueous compatibility during labeling and purification. The terminal alcohol also supports secondary derivatization routes, such as attachment to activated esters or conversion into additional functional groups for probe assembly and multistep construct building. This makes Azido-PEG4-alcohol a practical reagent for generating azide-bearing intermediates used in imaging probe development, affinity reagents, and modular chemical biology tools.

2. PEGylated Surface Functionalization

Azido-PEG4-alcohol serves as a convenient PEG-based azide source for modifying material surfaces where hydroxyl-terminated PEG segments help tune wettability, reduce nonspecific adsorption, and provide a defined distance between the surface and the click-reactive site. In biomaterials and diagnostic reagent development, azide-functional coatings and thin-film modifications are commonly prepared using PEG linkers to improve reproducibility of subsequent conjugation steps with alkyne-bearing ligands, nanoparticles, or capture molecules. The reagent’s compact PEG4 architecture supports scalable surface chemistry workflows, including grafting strategies that yield stable, water-compatible interfaces for downstream assembly of multicomponent diagnostic and research platforms. Azido-PEG4-alcohol is therefore frequently incorporated into surface functionalization schemes that require a reliable azide handle with improved handling characteristics.

3. Molecular Imaging Probe Assembly

Azido-PEG4-alcohol is used to prepare azide-functional imaging reagents and labeling intermediates for molecular imaging and fluorescence-based detection platforms. The PEG4 spacer helps maintain probe solubility and reduces local crowding around the azide group, which can be important when conjugating bulky imaging reporters or when coupling to targeting motifs through click chemistry. Teams developing small-molecule or polymeric imaging constructs often rely on Azido-PEG4-alcohol to introduce a standardized azide moiety that can be rapidly coupled to alkyne-functional reporters, affinity ligands, or scaffold components. The hydroxyl terminus further supports flexible downstream modification, enabling the creation of probe architectures with controlled hydrophilicity and consistent conjugation geometry. As a result, Azido-PEG4-alcohol is a common building block in probe assembly pipelines where modularity and reproducible conjugation are prioritized.

4. Diagnostic Reagent and Capture Chemistry

Azido-PEG4-alcohol is frequently incorporated into diagnostic reagent development and assay reagent manufacturing as an azide-containing linker for preparing capture surfaces and reagent conjugates. In assay workflows, azide handles are used to attach recognition elements, signal reporters, or polymer carriers via click conjugation, allowing efficient assembly of multicomponent systems under conditions compatible with sensitive biomolecular components. The PEG4 spacer and terminal alcohol promote aqueous handling and can improve conjugate stability during coupling, washing, and storage steps typical of assay reagent preparation. By providing a controllable distance and a hydrophilic linkage environment, Azido-PEG4-alcohol supports consistent performance of reagent constructs that require modular, click-based attachment of alkyne-bearing partners. This makes it a practical azide building block for constructing standardized reagent libraries and scalable assay components.