Superparamagnetic core-shell polymer particles for efficient purification of his-tagged proteins

Abstract

Magnetic core-shell Fe₃O₄@SiO₂@poly(styrene-alt-maleic anhydride) spheres enriched with Ni-NTA on their surface have been prepared by precipitation polymerization. The spheres have a core composed of superparamagnetic polycrystalline magnetite having a uniform size of ∼220 nm, endowing the spheres with excellent magnetic responsivity and dispersity. The shell composition of poly(styrene-alt-maleic anhydride) allows the incorporation of more Ni-NTA affinity sites onto the surface of the magnetic spheres. Owing to the multivalency effect, the separation capacity of His-tagged proteins by the as-prepared Fe₃O₄@SiO₂@polymer/Ni-NTA composites was four times as that by Fe₃O₄@SiO₂/Ni-NTA, making them particularly promising for the magnetic separation of low-concentration His-tagged proteins. The magnentic polymer hybrid particles also exhibited excellent performance in the direct separation of His-tagged proteins from cells lysates.