DBCO-NH-PEG4-maleimide | CAS 1480516-75-3

DBCO-NH-PEG4-maleimide is a bifunctional click chemistry reagent that combines a strained cyclooctyne (DBCO) for copper-free strain-promoted azide–alkyne cycloaddition (SPAAC) with a maleimide handle for selective thiol conjugation. The PEG4 spacer improves aqueous solubility and helps reduce steric constraints during bioconjugation, making the reagent well suited for modular labeling workflows. This structure is commonly used to build multi-component probes, surface coatings, and biomaterial functionalization schemes where orthogonal conjugation steps are required.

1. Dual-Handle Biomolecule Labeling

DBCO-NH-PEG4-maleimide is widely used to generate dual-functional biomolecule conjugates by first installing the maleimide onto thiol-containing targets such as cysteine-terminated peptides, reduced antibodies, or engineered protein tags, and then using the DBCO group for subsequent SPAAC coupling to azide-bearing partners. This orthogonal design supports sequential assembly of complex constructs used in chemical biology, including multi-epitope labeling strategies and modular probe generation. The PEG4 linker helps maintain reactivity in aqueous buffers and can improve conjugate homogeneity when attaching biomolecules that are sensitive to crowding near the reactive sites.

2. Surface Functionalization For Assays

DBCO-NH-PEG4-maleimide is employed for functionalizing sensor surfaces, microarray platforms, and assay substrates through thiol-reactive maleimide coupling to surface-presented thiols or thiol-terminated linkers. After immobilization, the DBCO functionality enables rapid, copper-free attachment of azide-functional capture reagents, fluorescent reporters, or affinity ligands via SPAAC. This approach is especially useful in workflow designs that benefit from orthogonal immobilization steps, where the surface is prepared first and then populated with specific azide-tagged components to tune assay format, signal generation, and multiplexing layouts.

3. Protein And Peptide Conjugates

DBCO-NH-PEG4-maleimide supports the preparation of protein and peptide conjugates used as research reagents for tracking, binding studies, and reagent standardization in molecular imaging and biomolecular engineering. The maleimide group reacts with accessible thiols to attach the PEG-spaced DBCO moiety to proteins or peptides, creating a stable intermediate that can later be coupled to azide-bearing dyes, affinity handles, or imaging scaffolds through SPAAC. This reagent format is commonly selected when researchers need a controlled, modular route to introduce a click handle onto biomolecules while minimizing interference with other functional groups.

4. Nanoparticle And Material Coatings

DBCO-NH-PEG4-maleimide is applied to nanoparticle and biomaterials surface modification where thiol chemistry is used to anchor the reagent to polymer, lipid, or material interfaces, followed by SPAAC-driven attachment of azide-functional components. The PEG4 spacer can improve colloidal stability and reduce nonspecific interactions by providing a hydrophilic tether between the surface and the reactive DBCO group. Downstream, the DBCO handle is used to decorate particles, vesicles, or scaffold materials with azide-tagged targeting motifs, imaging reporters, or reactive ligands, enabling customizable material architectures for advanced research tool development.