Propargyl-PEG7-acid | CAS 2093154-00-6

Propargyl-PEG7-acid is a PEG-based alkyne building block designed for copper-free or copper-assisted click chemistry workflows, where the terminal propargyl group serves as the click handle for covalent ligation. The extended PEG spacer and carboxylic acid functionality make it compatible with aqueous bioconjugation environments and with downstream immobilization or surface coupling strategies. As a research-grade reagent, it is commonly selected to introduce a defined alkyne functionality into PEGylated materials, molecular probes, and conjugation-ready linkers for materials science and chemical biology.

1. PEGylated Probe Functionalization

Propargyl-PEG7-acid is widely used to incorporate an alkyne handle into PEGylated imaging and detection probes, enabling subsequent conjugation to azide-bearing partners used in click-based labeling workflows. The PEG7 chain helps maintain solubility and reduces nonspecific interactions during probe assembly, which is particularly valuable for fluorescent, affinity, or mass-tagged probe formats that must remain stable in aqueous buffers. The terminal carboxylic acid also supports straightforward tethering to carrier scaffolds used in probe construction, such as polymer backbones or bead surfaces, allowing probe libraries to be generated with consistent linker length and spacing.

2. Surface and Material Immobilization

Propargyl-PEG7-acid is commonly applied in biomaterials and interface engineering to introduce clickable alkyne functionality onto surfaces and polymeric materials that will later be patterned or functionalized with azide-containing biomolecules. The carboxylic acid enables coupling to amine-rich substrates or activation-based attachment chemistries used in coating and immobilization pipelines, while the PEG spacer provides a hydrated, antifouling-like environment that can improve accessibility of the click handle. This makes the reagent useful for constructing clickable hydrogel networks, functional films, and solid supports intended for subsequent modular attachment of ligands, capture reagents, or imaging tags.

3. Linker Design for Bioconjugation

Propargyl-PEG7-acid is frequently selected as a defined PEG linker for bioconjugation workflows that require an alkyne moiety positioned at a controlled distance from a functional group. The reagent’s bifunctional character supports conjugation strategies where the carboxyl group is first used to attach the linker to a carrier (such as a polymer, nanoparticle, or scaffold), and the alkyne is reserved for later click ligation to azide-bearing targets. In chemical biology and molecular imaging tool development, this approach helps standardize conjugate architecture, improving reproducibility across probe batches and enabling rapid exchange of azide partners without redesigning the entire tether.

4. Nanoparticle and Bead Conjugates

Propargyl-PEG7-acid is used to prepare clickable nanoparticle and bead conjugates where PEG spacing is important for colloidal stability and for maintaining accessibility of reactive handles. The carboxylic acid functionality supports tethering to particle surfaces through common coupling approaches used in research reagent manufacturing, while the terminal alkyne provides a robust handle for downstream click assembly with azide-functional biomolecules, reporters, or affinity reagents. This enables scalable production of modular conjugate sets used in assay development, multiplex labeling, and materials-directed studies requiring consistent linker length and minimized steric hindrance.