Preparation of hollow nickel silicate nanospheres for separation of His-tagged proteins

Abstract

Hollow nickel silicate nanospheres (NiSiO₃ NSs) with hierarchical shells were hydrothermally synthesized by using silica spheres as a template. The NiSiO₃ NSs have an average diameter of 250 nm with a shell thickness of 50 nm, and the hierarchical shell consists of a large number of sheets. By taking advantage of the high affinity of Ni²⁺ toward histidine-tagged (His-tagged) proteins, hollow NiSiO₃ NSs can be used to enrich and separate His-tagged proteins directly from a mixture of lysed cells. Results indicated that the hollow NiSiO₃ NSs presented negligible nonspecific protein adsorption and a high protein binding ability with a high binding capacity of 13.2 mmol g⁻¹. Their specificity and affinity toward His-tagged proteins remained after recycling 5 times. The hollow NiSiO₃ NSs are especially suitable for rapid purification of His-tagged proteins.