Preparation of Fe3O4 and CoFe2O4 nanoparticles with cellular compatibility via the histidine assistance

In order to obtain magnetic nanoparticles (NPs) coated with small biomolecules, histidine (His)-coated iron oxide (His-Fe3O4) and cobalt ferrite (His-CoFe2O4) with a polycrystalline structure were prepared by a simple liquid deposition method at room temperature. The growth mechanism for His-Fe3O4 and His-CoFe2O4 NPs was preliminarily explained, and their growth conditions, such as His concentrations, Co/Fe ratio, the synthesis time, were studied. The analysis of Fourier transform infrared spectra and X-ray photoelectron spectroscopy results indicated that the as-prepared particles were conjugated with the small histidine molecules. The hysteresis loops of NPs revealed their good magnetic property. L929 Cell tests indicate the good cytocompatibility of His-Fe3O4 and His-CoFe2O4 NPs, which is better than the previous prepared magnetic NPs with the polymer.