Co-assemblies of polyoxometalate {Mo 72 Fe 30 }/double-tailed magnetic-surfactant for magnetic-driven anchorage and enrichment of protein.

Covalent grafting and electrostatic-driven assembly have been two strategies in constructing well-defined polyoxometalate (POM) assemblies to produce specific morphologies and desirable properties. The modification of anionic counter-ions of amphiphilic compounds in POM-surfactant hybrid systems is still unexploited. Herein, we report the co-assembly of a synthetic double-tailed magnetic surfactant (MagSurf), (C ₁₈ ) ₂ C ₂ N ⁺ [FeCl ₄ ] ^- , and POM, {Mo ₇₂ Fe ₃₀ }. The magnetic aggregate (POM/MagSurf) results from the building up hierarchical structures at a time-dependent interface. In this construct, both the MagSurfs and {Mo ₇₂ Fe ₃₀ } POMs contribute to and mutually strengthen the magnetization of the designed magnetic assembles. Interestingly, the POM/MagSurf aggregates are compatible with aqueous mixtures and successfully employed to serve as magnetic transporting vehicles to anchor and deliver a protein molecule, myoglobin (Mb). Upon applying a magnetic field (0.3 T), the magnetic aggregates induced a directional migration and enrichment of the Mb protein (71-90%). During this process, the protein/POM/MagSurf complexes exhibited strong interactions facilitating stable anchoring and efficient enrichment of the Mb.
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