Synthesis of hierarchical nickel anchored on Fe3O4@SiO2 and its successful utilization to remove the abundant proteins (BHb) in bovine blood

A hierarchical nickel shell anchored on silica coated magnetic Fe3O4@ SiO2 nanospheres (MNPs) has been designed and constructed, which combines the capacity of effective adsorption of protein bovine hemoglobin (BHb) and selective deletion of BHb from real bovine blood samples. Firstly, -NH2 modified silica/magnetite nanoparticles (Fe3O4@ SiO2-NH2) were synthesized by combining a sol-gel method and a refluxing process. The Fe3O4@ SiO2-NH2 composites revealed a core-shell structure, and the thickness of the silica shell can be easily adjusted by controlling the amount of ammonium solution. Then, the hierarchical nickel shells were anchored on the surface of Fe3O4@ SiO2-NH2 by reducing Ni2+ between the solid Fe3O4@ SiO2-NH2 and nickel solution with NaBH4. By taking advantage of the high affinity of Ni2+ on the shell surface toward His-tagged proteins and the fast response toward an assistant magnet, the hetero-nanoparticles can be applied to selectively bind to and magnetically separate BHb from the bovine blood. Significantly, it is expected that this approach can be extended to other bimolecular separation and purification processes.