Synthesis and Characterization of Fe10BO3/Fe3O4/SiO2 and GdFeO3/Fe3O4/SiO2: Nanocomposites of Biofunctional Materials

Cancer is one of the leading causes of death worldwide; with many different types, it kills thousands of people every day. Various types of treatments have been developed to treat cancer, and new approaches that are currently under investigation include boron neutron capture therapy (BNCT) and gadolinium neutron capture therapy (GdNCT). Neutron capture therapy is primarily used to treat brain tumors, such as glioblastoma, a particularly aggressive type of brain tumor that is difficult to treat by conventional means such as radiation therapy. BNCT and GdNCT involve a bimodal approach to treatment, utilizing a cancer-specific drug and a neutron source (neutron beam). The approach is based on the ability of a boron isotope (B) to absorb neutrons and emit localized cell-killing particles. The main mechanism that takes place in BNCT is the absorption of a neutron to convert B to B, with the release of He , Li , and energy. The energy that is released can then destroy the tumor cell. Gadolinium also attracted interest for its potential use in neutron capture therapy because it is the element with the highest cross-sectional value for thermal neutrons—2.55 10 b and 6.10 10 b for Gd and Gd, respectively. In fact, the thermal neutron value of Gd (2.55 10 b) is 65 times that of B, and it releases Auger electrons, internal conversion electrons, g-ray and X-ray after the capture of a single thermal neutron. Targeted delivery of an anticancer drug is very desirable, as most of the commonly used agents have serious side effects associated with their use due to undesirable interactions with healthy cells. Moreover, targeted delivery can potentially enhance the therapeutic efficacy. Research on nanomaterials has grown explosively in the last few years, including an increased emphasis on developing nanomaterials as drug delivery vehicles. 10] The size of such delivery vehicles (<1000 nm) has attracted wide interest in the field of drug targeting. Nanomaterial-based drug systems provide the advantage of being able to penetrate cell membranes through minuscule capillaries in the cell wall of rapidly dividing tumor cells, while at the same time having low cytotoxicity toward normal cells. Nanomaterials have been found to have favorable interaction with the brain blood vessel endothelial cells of mice, and thus they might have the possibility of being transported to other brain tissues, making them potential neutron capture therapy agents. In theory, in BNCT and GdNCT nanomaterials, a large number of boron and gadolinium atoms could be incorporated, thereby lowering the dose requirement for delivering critical amounts of B and Gd to tumor cells. Accordingly, improvement of the drug storage capacity is very important. Magnetic nanoparticles are being studied in terms of their highly promising applications in biology and medicine, including magnetic cell separation, magnetic resonance imaging (MRI) contrast enhancement, and magnetic targeted drug delivery for cancer magnetic hyperthermia. MRI is a noninvasive technique for obtaining real-time three-dimensional images of the interior of solids (particularly cells), tissues, and organs. But magnetic nanoparticles tend to aggregate due to strong magnetic dipole–dipole attraction between particles brought together by van der Waals interparticle attractions and their inherently large surface energy. Therefore, coating agents, such as surfactants or capping ligands with some specific functional groups, have been used to modify these particles in order to prevent the sedimentation and to obtain better surface properties. Silicates have attracted significant interest because of their rich structural chemistry, which makes the development of new structures and functionalities possible. Amorphous silica with a nontoxic nature, tunable diameter, and very high specific surface area with abundant Si OH bonds on the surface are promising candidates for use as carriers in drug delivery systems. Thus, nanocomposites of SiO2 and magnetic particles [a] Prof. S. Gao, Prof. T. Xu, Prof. N. S. Hosmane Department of Chemistry and Biochemistry Northern Illinois University 1425 W. Lincoln Hwy, DeKalb, IL 60115-2862 (USA) E-mail : [email protected] [b] Prof. S. Gao, X. Liu School of Chemistry and Materials Science Ludong University Yantai, 264025 (P. R. China) [c] X. Ma, Prof. Z. Shen, Prof. A. Wu Division of Functional Materials and Nano-devices Ningbo Institute of Materials Technology & Engineering Chinese Academy of Sciences Ningbo, 315201 (P. R. China) [d] Dr. Y. Zhu Institute of Chemical and Engineering Sciences (ICES) 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore) 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.