Selective binding and magnetic separation of histidine-tagged proteins using Ni2+-decorated Fe3O4/hydroxyapatite composite nanoparticles

Fe3O4/hydroxyapatite (Fe3O4/HAP) nanoparticles (NPs) were synthesized by hydrothermal method. The obtained NPs have excellent magnetic responsibility and can immobilize metal ions. After chelating Ni2+ ions, Fe3O4/HAP-Ni2+ NPs can be used to enrich histidine-tagged (His-tagged) proteins directly from the mixture of lysed cells. Results show that Fe3O4/HAP-Ni2+ NPs present negligible nonspecific protein adsorption and high protein binding activity with the saturation capacity being 12.98 mmol/g. Their separation capcity towards His-tagged proteins was remained after 4 times recycling. They are especially suitable for rapid purification of His-tagged proteins.

• Fe3O4/HAP NPs with excellent magnetic responsibility were prepared by hydrothermal route.
• Fe3O4/HAP NPs are used as novel adsorbents through chelating Ni2+ ions.
• Fe3O4/HAP NPs can capture directly His-tagged proteins from the mixture of lysed cells.
• HAP/IDA-Ni2+ present negligible nonspecific adsorption and high protein binding ability.