(2-Pyridyldithio)-PEG4-propargyl | CAS 2170240-99-8

(2-Pyridyldithio)-PEG4-propargyl is a PEG-based, thiol-reactive click chemistry reagent that combines a pyridyl disulfide handle with a terminal propargyl group for copper-free or copper-assisted alkyne-based labeling workflows. As a disulfide-containing linker, it is commonly used to introduce a bioorthogonal alkyne functionality onto thiol-bearing biomolecules, while the PEG4 spacer supports improved solubility and reduced nonspecific interactions in labeling and conjugation experiments. This reagent is frequently selected for building modular probe and material platforms where subsequent click attachment of dyes, affinity tags, or imaging handles is required.

1. Thiol-Functional Bioconjugation

(2-Pyridyldithio)-PEG4-propargyl is widely used to functionalize cysteine- or thiol-containing biomolecules with a propargyl group, enabling downstream alkyne-reactive click attachment to reporters such as fluorophores, biotin analogs, or affinity ligands. The pyridyl disulfide motif provides a convenient thiol exchange strategy for installing the clickable handle under conditions compatible with many labeling workflows, while the PEG4 spacer helps maintain conjugate solubility and reduces aggregation during probe preparation. Researchers in chemical biology and molecular imaging often rely on this reagent to generate alkyne-bearing conjugates that can be coupled to azide-functional partners in a modular, stepwise manner.

2. Fluorophore And Affinity Tag Labeling

(2-Pyridyldithio)-PEG4-propargyl supports the preparation of fluorescent and affinity-tagged reagents by first introducing a terminal alkyne onto target scaffolds, followed by click coupling to azide-functional dyes or capture elements. This two-step design is particularly useful when probe composition must be varied systematically, such as when screening different reporter colors, brightness regimes, or enrichment handles for pull-down and detection assays. The PEG4 linker contributes to more consistent labeling behavior in aqueous buffers, which is valuable for generating reproducible probe sets for imaging reagent development and assay optimization.

3. PEG Linker Material Surface Modification

(2-Pyridyldithio)-PEG4-propargyl is applied in biomaterials and surface chemistry workflows to introduce clickable functionality onto thiol-reactive surfaces or thiol-functionalized coatings prior to subsequent attachment of azide-bearing polymers, biomolecule layers, or imaging moieties. The PEG4 segment helps tune interfacial hydration and spacing, supporting more uniform presentation of functional groups on material substrates such as hydrogel components, polymer films, and scaffold surfaces used in research-grade platform building. Teams developing molecular imaging tools and diagnostic reagent prototypes often use this approach to create stable, modular surfaces that can be further functionalized without redesigning the entire material synthesis.

4. Modular Probe Platform Building

(2-Pyridyldithio)-PEG4-propargyl is commonly selected for constructing modular probe platforms where alkyne introduction is separated from final reporter installation, allowing rapid exchange of azide partners to generate families of related reagents. This strategy is attractive for laboratories that need consistent handle chemistry across multiple targets, including enzyme substrates, binding proteins, and engineered affinity scaffolds, while maintaining a standardized click-compatible output. The reagent’s disulfide-based thiol reactivity and PEG4 spacing make it a practical choice for producing click-ready intermediates used in molecular imaging reagent development and research tool generation.