Ferroferric oxide/l-cysteine magnetic nanospheres for capturing histidine-tagged proteins

Abstract

Ferroferric oxide/L-cysteine (Fe₃O₄/Cys) nanospheres (NSs) have been successfully synthesized via a facile solvothermal route. Fe₃O₄/Cys NSs possessed high thiol group density and saturation magnetization (M_s) of 84.6 emu g⁻¹. The prepared magnetic NSs are biocompatible and manipulatable by an external magnetic force. After chelating Ni²⁺ ions, Fe₃O₄/Cys-Ni²⁺ NSs were used to enrich and purify histidine-tagged (His-tagged) proteins directly from the mixture of lysed cells without pretreatment. It has been found that Fe₃O₄/Cys-Ni²⁺ NSs present negligible nonspecific protein adsorption and high protein binding activity with the saturation capacity being 53.2 μg mg⁻¹ and they are especially suitable for rapid purification of His-tagged proteins.