Efficient purification of His-tagged protein by superparamagnetic Fe3O4/Au–ANTA–Co2 + nanoparticles

Superparamagnetic Fe3O4/Au nanoparticles were synthesized and surface modified with mercaptopropionic acid (MPA), followed by conjugating Nα,Nα-Bis(carboxymethyl)-l-lysine hydrate (ANTA) and subsequently chelating Co2 +. The resulting Fe3O4/Au–ANTA–Co2 + nanoparticles have an average size of 210 nm in aqueous solution, and a magnetization of 36 emu/g, endowing the magnetic nanoparticles with excellent magnetic responsivity and dispersity. The Co2 + ions in the magnetic nanoparticle shell provide docking site for histidine, and the Fe3O4/Au–ANTA–Co2 + nanoparticles exhibit excellent performance in binding of a His-tagged protein with a binding capacity of 74 μg/mg. The magnetic nanoparticles show highly selective purification of the His-tagged protein from Escherichia coli lysate. Therefore, the obtained Fe3O4/Au–ANTA–Co2 + nanoparticles exhibited excellent performance in the direct separation of His-tagged protein from cell lysate.