Co-assemblies of polyoxometalate {Mo72Fe30}/double-tailed magnetic-surfactant for magnetic-driven anchorage and enrichment of protein

Abstract 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.