Sulfo DBCO-PEG4-Maleimide | CAS 2055198-07-5

Sulfo DBCO-PEG4-Maleimide is a water-soluble DBCO (dibenzocyclooctyne) click chemistry reagent bearing a PEG4 spacer and a maleimide functional group. It is designed for strain-promoted azide–alkyne cycloaddition (SPAAC) compatibility while providing a second, thiol-reactive handle through the maleimide for bioconjugation workflows. The sulfonate improves aqueous handling and reduces nonspecific hydrophobic interactions, making it well suited for labeling, surface modification, and probe assembly in chemical biology and biomaterials research.

1. Two-Step Probe Conjugation

Sulfo DBCO-PEG4-Maleimide is commonly used to build modular labeling reagents where a thiol-reactive attachment is required before or after SPAAC-based coupling. Researchers employ the maleimide to install the DBCO-bearing moiety onto thiolated biomolecules such as peptides, proteins, antibodies, nanobodies, or enzyme fragments, then use the DBCO group to react with azide-functional partners for fluorescent probe generation, affinity reagent assembly, or multicolor labeling strategies. The PEG4 linker helps maintain conjugate accessibility and reduces steric constraints that can otherwise limit labeling efficiency in complex biological mixtures.

2. Biomaterial Surface Functionalization

Sulfo DBCO-PEG4-Maleimide is frequently applied for functionalizing biomaterial surfaces and interfaces that present accessible thiols or can be engineered to do so, enabling subsequent azide-based patterning. In materials and surface chemistry workflows, the maleimide is used to tether the DBCO functionality to thiol-containing coatings, polymer brushes, or biomolecule-anchored layers, while the sulfonated DBCO component supports aqueous SPAAC coupling to azide-bearing ligands, reporters, or crosslinking partners. This approach is used to create clickable surfaces for biosensing platforms, cell-interaction studies, and spatially resolved labeling of engineered materials.

3. Protein Labeling and Imaging Reagents

Sulfo DBCO-PEG4-Maleimide is well suited for preparing protein imaging and detection reagents that require controlled conjugation chemistry and aqueous compatibility. The reagent’s maleimide group enables site-selective attachment to thiol-containing proteins or protein fragments (including those generated by controlled reduction or engineered cysteine residues), and the DBCO handle supports follow-on SPAAC with azide-tagged fluorophores, affinity tags, or imaging reporters. The PEG4 spacer and sulfonate functionality are particularly valuable when working with dilute labeling conditions, complex protein mixtures, or when minimizing nonspecific adsorption is important for downstream imaging reagent performance.

4. Multimodal Diagnostic Platform Building

Sulfo DBCO-PEG4-Maleimide is used in research settings to assemble multimodal diagnostic and analytical platforms that combine distinct functional components through orthogonal click-compatible handles. Maleimide-driven conjugation provides a practical route to incorporate DBCO-bearing chemistry onto thiolated capture molecules, nanoparticles, or scaffold polymers, and the DBCO group then enables SPAAC coupling to azide-functional reporters such as fluorescent dyes, luminescent labels, or nucleic-acid/aptamer tags. This modular assembly strategy supports iterative optimization of reagent architecture for array-based assays, multiplexed readouts, and probe libraries where consistent aqueous conjugation is required across many targets.