Different kinds of nanospheres are used in magnetic nanosphere fabrication for bioapplications. In this paper, we report a successful synthesis of magnetic hollow silica nanospheres (MHSNS). The MHSNS were fabricated with a one step coating of Fe3O4 magnetic nanoparticles (NPs)(∼10nm) and silica on nanosized (20–100nm) spherical calcium carbonate (CaCO3) surface under alkaline conditions, in which the nanosized CaCO3 were used as nanotemplates and tetraethoxysilane and magnetic NPs were used as precursors. The as-synthesized nanoshperes were immersed in an acidic solution to remove nanosized CaCO3, forming MHSNS. The MHSNS were characterized by SEM, TEM, and SQUID. SEM and TEM results showed that a smooth surface of MHSNS and a thin layer of silica (∼10nm) embedded with the magnetic NPs was successfully formed. No nanosized CaCO3 nanotemplates were observed. SQUID measurement demonstrated that magnetization of MHSNS was dependent on temperature, exhibiting superparamagnetism. The MHSNS have potential applications in biomedicine and bioseparation.
Shao, L.; Carantu, Dumitru; Chen, J. F.; O'Connor, C. J.; and Zhou, W. L., "Fabrication of magnetic hollow silica nanospheres for bioapplications" (2005). Mechanical Engineering Faculty Publications and Presentations. 16.
Journal of Applied Physics