Preparation and Characterization of Iron Oxide–Silica Composite Particles Using Mesoporous SBA-15 Silica as Template and Their Internalization Into Mesenchymal Stem Cell and Human Bone Cell Lines

摘要

A new procedure for preparing iron oxide–silica nanocomposite particles using SBA-15 mesoporous silica as a template is described. These composite materials retained the 2-D hexagonal structure of the SBA-15 template. Transmission electron micrograms of the particles depicted the formation of iron oxide nanocrystals inside the mesochannels of SBA-15 silica framework. Powder x-ray diffraction showed that the iron oxide core of the composite particles consists of a mixture of maghemite ( $gamma$-Fe $_{2}$O $_{3}$) and heamatite ( $alpha$-Fe $_{2}$O $_{3}$), which is the predominant component. Superconducting quantum interference device (SQUID) magnetometry studies showed that these iron oxide–silica composite materials exhibit superparamagnetic properties. On increasing the iron oxide content, the composite particles exhibited a stronger response to magnetic fields but a less homogeneous core, with some large iron oxide particles which were thought to be formed outside the mesochannels of the SBA-15 template. Internalization of these particles into human cell lines (mesenchymal stem cells and human bone cells), which indicates their potential in medicine and biotechnology, is also discussed.