Mal-​PEG4-​propargyl | CAS 1262681-30-0

Mal-​PEG4-​propargyl is a PEG-based propargylated linker designed for copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) click chemistry. The reagent combines a hydrophilic, biocompatible polyethylene glycol spacer with a terminal alkyne handle, enabling robust conjugation to azide-bearing biomolecules, surfaces, and polymeric materials. Its PEG4 architecture supports aqueous labeling workflows and helps improve solubility and accessibility of the reactive group in downstream probe and material assembly.

1. Biomolecule Conjugation

Mal-​PEG4-​propargyl is widely used to introduce a defined alkyne functionality onto biomolecular constructs that will later be coupled to azide-tagged partners via CuAAC. Researchers employ it for preparing antibody–polymer conjugates, enzyme labeling reagents, and nucleic-acid or peptide conjugation intermediates where the PEG spacer helps maintain colloidal stability and reduces nonspecific interactions during labeling and purification. The reagent’s terminal propargyl group is particularly useful when the azide partner is already installed on the target, allowing modular assembly of multicomponent bioconjugates for analytical and discovery workflows.

2. Surface And Material Functionalization

Mal-​PEG4-​propargyl supports the creation of clickable interfaces on engineered materials, including polymer films, hydrogel networks, and functionalized nanoparticles, where an alkyne-bearing PEG tether is required for subsequent azide-directed coupling. In materials science and chemical biology, it is commonly incorporated to generate reactive coatings or to pattern surfaces with bioorthogonal handles for immobilizing ligands, affinity reagents, or capture probes. The PEG4 spacer helps mitigate steric crowding near the surface and can improve uniformity of coupling when building complex, multivalent material architectures.

3. Molecular Imaging Probes

Mal-​PEG4-​propargyl is used as a practical PEG–alkyne component in the assembly of imaging and detection reagents that rely on azide–alkyne click coupling for modular synthesis. Probe developers often attach fluorophores, quencher systems, or other imaging moieties to azide-functional scaffolds and then use Mal-​PEG4-​propargyl to install the complementary alkyne handle on carriers such as targeting ligands or probe backbones. The hydrophilic PEG spacer supports aqueous solubility and can help preserve probe behavior during conjugation and purification steps, which is valuable for high-throughput reagent preparation.

4. Diagnostic Reagent Building Blocks

Mal-​PEG4-​propargyl is commonly selected as a linker building block for preparing diagnostic and assay reagents that require controlled, site-specific attachment of capture or reporting components through CuAAC. In assay development workflows, the reagent is used to generate alkyne-functional intermediates that can be coupled to azide-bearing tags, affinity reagents, or labeling partners to form multicomponent detection systems. The PEG4 chain contributes to improved handling in aqueous buffers and supports conjugate stability during iterative optimization of assay formats and reagent panels.