N-(PEG2-C2-acid)-N-bis(PEG2-propargyl) | CAS 2100306-49-6

N-(PEG2-C2-acid)-N-bis(PEG2-propargyl) is a PEGylated, multifunctional propargyl-bearing click chemistry reagent designed for copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) and related alkyne-based bioconjugation workflows. The molecule combines a reactive propargyl functionality with a PEG2 spacer architecture and an acid handle that supports aqueous compatibility and downstream coupling strategies. This reagent is commonly selected when researchers need controlled incorporation of multiple alkyne groups into PEG-rich linkers for labeling, surface modification, and probe construction in chemical biology and biomaterials research.

1. Multivalent Protein Labeling

N-(PEG2-C2-acid)-N-bis(PEG2-propargyl) is used to introduce two alkyne handles per reagent into protein conjugates via CuAAC, enabling higher labeling density and improved signal-to-background strategies for analytical and imaging workflows. The PEG2 framework helps maintain solubility and reduces nonspecific interactions during conjugation and purification, which is particularly valuable for labeling enzymes, antibodies, and protein scaffolds that are sensitive to harsh conditions. The acid functionality also supports compatibility with common buffer systems and can be leveraged during downstream linker assembly when preparing multi-component conjugates.

2. PEG Linker Construction

N-(PEG2-C2-acid)-N-bis(PEG2-propargyl) serves as a building block for constructing PEG-rich linkers and surface-tethered architectures that require alkyne functionality for subsequent click coupling. Researchers incorporate this reagent into modular conjugation schemes where PEG spacing is used to tune hydrophilicity, accessibility of reactive groups, and overall conjugate stability in aqueous media. The bis(propargyl) design supports multivalent attachment strategies, which are frequently used to build libraries of labeled biomolecules, affinity reagents, and standardized reagent platforms for consistent downstream assembly.

3. Surface and Material Functionalization

N-(PEG2-C2-acid)-N-bis(PEG2-propargyl) is applied to functionalize biomaterial surfaces and polymeric substrates with alkyne groups for later CuAAC attachment of azide-bearing ligands, biomolecules, or fluorescent tags. The PEG2 segments contribute to antifouling-like behavior and help preserve reactivity at interfaces where nonspecific adsorption can otherwise hinder effective labeling. This reagent is commonly used in the development of clickable coatings, hydrogel modification strategies, and patterned materials where spatially controlled azide–alkyne coupling is used to generate functional surfaces for chemical biology assays and materials characterization.

4. Molecular Imaging Probe Assembly

N-(PEG2-C2-acid)-N-bis(PEG2-propargyl) is frequently incorporated into probe synthesis pipelines to provide reliable alkyne handles for click-based attachment of imaging reporters, targeting motifs, or reporter payloads that are introduced as azide-functionalized components. The dual propargyl functionality supports multivalent probe architectures that can enhance labeling uniformity across conjugate populations, while the PEG2 environment improves handling in water-based probe formulation and reduces aggregation during reagent preparation. The acid handle can be useful for integrating the reagent into broader linker designs for assembling complex, modular imaging reagents used in fluorescence, luminescence, and microscopy-oriented chemical biology workflows.