m-PEG3-S-PEG4-propargyl | CAS 2055040-85-0

m-PEG3-S-PEG4-propargyl is a heterobifunctional PEG-based click chemistry reagent that incorporates a thioether-linked PEG architecture and a terminal propargyl group for copper-catalyzed azide–alkyne cycloaddition (CuAAC). The flexible, water-compatible PEG segments are commonly used to tune solubility, reduce nonspecific interactions, and provide a defined attachment handle for downstream conjugation workflows. Because the propargyl moiety enables standardized “click-to” coupling with azide-bearing partners, this reagent is frequently selected for building modular PEGylated probes, surface coatings, and biomaterial functionalization strategies.

1. PEGylated Probe Conjugation

m-PEG3-S-PEG4-propargyl is widely used to introduce a propargyl-bearing PEG spacer into imaging and sensing probes that are assembled via CuAAC with azide-functional reporters. Researchers use this reagent to improve aqueous compatibility and to control the effective distance between a targeting or recognition element and the signal tag, which can be important for probe stability and reduced background in complex assay matrices. The thioether-bridged PEG scaffold also supports robust handling during labeling workflows, enabling consistent coupling to azide-modified dyes, fluorophores, affinity tags, or imaging moieties.

2. Surface Functionalization for Biomaterials

m-PEG3-S-PEG4-propargyl is used to functionalize biomaterial surfaces and polymeric substrates where PEG spacers help mitigate nonspecific adsorption while maintaining reactive accessibility for subsequent click coupling. In materials research, the reagent serves as a propargylated PEG linker that can be immobilized or incorporated into coatings, hydrogels, and membrane-like platforms prior to reaction with azide-bearing ligands. This approach supports the preparation of antifouling, biointerface-active materials used in cell-adhesion studies, protein immobilization experiments, and modular platform development for assay and screening formats.

3. Multivalent Polymer and Nanoconjugates

m-PEG3-S-PEG4-propargyl is a practical building block for constructing multivalent polymer conjugates and PEGylated nanoconjugates through azide–alkyne click assembly. By providing a defined PEG chain length and a terminal alkyne, it helps researchers control conjugation density and spatial presentation on larger constructs such as PEG-coated nanoparticles, polymer brushes, and macromolecular carriers. Downstream, the propargyl handle enables rapid attachment of multiple azide-functional components, supporting the creation of modular libraries of conjugates for reagent development and mechanistic studies in chemical biology.

4. Linker for Affinity Reagent Assembly

m-PEG3-S-PEG4-propargyl is commonly incorporated into workflows that generate affinity reagents and binding tools using CuAAC between propargylated PEG linkers and azide-functional biomolecular components. The PEG spacer provided by this reagent supports improved solubility and can help preserve the accessibility of binding groups by reducing steric crowding at the conjugation site. Teams developing research-grade pull-down reagents, affinity capture constructs, and labeled binding partners often select this type of PEG–propargyl linker to standardize coupling chemistry while maintaining compatibility with aqueous bioconjugation conditions.