Synthesis and in vitro evaluation of toxicity of silica-coated magnetite nanoparticles

Magnetic iron oxide nanoparticles properly coated with silica may be interesting in molecular biology, particularly as an auxiliary diagnostic material in biomedicine. This paper describes the coating of superparamagnetic magnetite nanoparticles with amorphous silica by sol-gel process using tetraethoxysilane. The physical-chemical characterization of the magnetite powder before and after silica-coating was performed by X-ray diffraction, Fourier-transform infrared, and zeta potential. The in vitro biocompatibility of the samples was analyzed by the viability/proliferation and collagen secretion capability of incubated osteoblasts in the presence of the composites. In summary, it was demonstrated that osteoblast viability decreased to about 20% in the presence of silica-coated magnetite nanoparticles when compared to the control group result. Moreover, the silica-coated magnetite nanoparticles did not alter osteoblast collagen secretion. The in vitro preliminary evaluation showed that silica-coating magnetite nanoparticles did not produce any severe alteration in biocompatibility. Further investigations are required to better understand the biocompatibility of silica-coated magnetite nanoparticles in biomedical applications. (C) 2008 Elsevier B.V. All rights reserved.