Azido-PEG5-alcohol | CAS 86770-68-5

Azido-PEG5-alcohol is a PEG-based azide building block designed for copper-free and copper-mediated click chemistry workflows, where the azide handle enables efficient conjugation to complementary alkyne partners. The reagent combines a terminal azide with a flexible, hydrophilic PEG5 spacer and a primary alcohol functional group, supporting downstream derivatization and stable incorporation into biomolecule-, polymer-, or surface-based constructs. Its PEG-mediated solubility and spacing characteristics make it a widely used intermediate for preparing clickable linkers, labeling reagents, and functional materials for chemical biology and molecular imaging research.

1. Biomolecule PEGylation Linkers

Azido-PEG5-alcohol is commonly used as a clickable PEG linker for attaching functional tags to proteins, peptides, and nucleic-acid-associated conjugates via azide–alkyne cycloaddition. Researchers value the PEG5 spacer for improving aqueous handling and reducing steric congestion at the conjugation site, which is particularly helpful when building multi-component labeling strategies or preparing homogeneous reagent sets for screening and assay development. The terminal alcohol also supports secondary functionalization steps, enabling the preparation of hydroxyl-terminated clickable conjugates that can be further modified for imaging probes, affinity reagents, or standardized reagent platforms.

2. Surface And Material Functionalization

Azido-PEG5-alcohol is used to introduce azide functionality onto polymeric and solid-phase materials, including PEG-modified coatings and functionalized resins, where subsequent click coupling to alkyne-bearing ligands or reporters yields stable, modular surfaces. Materials scientists and chemical engineers often select this reagent because the PEG spacer helps maintain surface wettability and can mitigate nonspecific interactions in complex buffers. The presence of the alcohol handle enables additional attachment chemistries to substrates or polymer backbones prior to or after click coupling, supporting reproducible fabrication of clickable interfaces for biosensing and research tool development.

3. Molecular Imaging Probe Building

Azido-PEG5-alcohol serves as a practical intermediate for constructing azide-functional imaging reagents and fluorescent or luminescent probe conjugates that require controlled linker length and water compatibility. In molecular imaging and chemical biology laboratories, the PEG5 unit helps tune probe hydrodynamic behavior and accessibility of the reactive handle, improving conjugate consistency when generating probe libraries for target-agnostic studies. The azide group provides a reliable click handle for installing reporter moieties through orthogonal alkyne partners, while the alcohol functionality supports iterative derivatization during probe optimization workflows.

4. Diagnostic Reagent Conjugation

Azido-PEG5-alcohol is frequently incorporated into diagnostic-reagent development pipelines as a linker for assembling clickable conjugates used in assay reagents, including affinity-based detection components and multiplex-ready labeling reagents. The PEG5 spacer supports solubility and helps maintain performance of conjugates in assay buffers where hydrophilicity and reduced aggregation are important for consistent reagent behavior. By providing an azide handle for click coupling and an alcohol for further derivatization, the reagent fits into modular manufacturing approaches for preparing standardized conjugate stocks and reagent kits used in research diagnostics and analytical assay development.