Graphene oxide coated Fe3O4@mSiO2 NPs for magnetic controlled bioimaging

Abstract

A novel GO coated porous magnetic NPs (Fe₃O₄@mSiO₂@GO) for bioimaging was synthesized. First, Fe₃O₄ magnetic NPs were prepared through a solvothermal reaction. Second, through a surfactant-templating approach with cetyltrimethylammonium bromide (CTAB) as a template, a mesostructured CTAB/SiO₂ composite was deposited on Fe₃O₄ NPs surfaces. Third, CTAB templates were removed to form a mesoporous SiO₂ shell, resulting in mesoporous magnetic (Fe₃O₄@mSiO₂) NPs. Forth, the magnetic NPs surfaces were functionalized with amino groups by (3-aminopropyl)triethoxysilane (APTES). Finally, the dye rhodamine B (RB) was loaded inside porous magnetic NPs, and the magnetic NPs surfaces were then wrapped with graphene oxide (GO) nanosheets. SEM analysis revealed that GO sheets have been successfully coated on magnetic NPs surfaces. The hysteresis loops analysis indicated that these magnetic NPs still retained strongly magnetic property. Furthermore, Fe₃O₄@mSiO₂@GO NPs could efficiently protect the loaded dye from releasing. In addition, MTT assay revealed that the RB loaded Fe₃O₄@mSiO₂@GO NPs exhibited insignificant cytotoxicity at moderate concentrations and the RB loaded Fe₃O₄@mSiO₂@GO NPs could undergo target-directed move under the action of a magnetic field. The noncytotoxic magnetic hybrids presented significant potential for applications in cell imaging.