Formation and Surface Modification of Fe3O4 Nanoparticles by Co-precipitation and Sol-gel Method

Abstract

Fe3O4 nanoparticles were synthesized by co-precipitation of Fe3+ and Fe2+ with NH4OH, and then silica was coated onto the surface of Fe3O4 by hydrolysis of TEOS. Coupling agent was also coupled with the surface of the nanoparticles and protein was immobilized. Morphology, particle size, and magnetic properties of the nanoparticles were characterized by TEM, DLS, and VSM, respectively. As a result, silica coated Fe3O4 nanoparticles with an average size of 15 nm were obtained and super-paramagnetic properties were achieved.