Preparation And Research Of Multifunctional Nanocomposites Based On Fe₃O₄@ZnO With Microwave-responsive Controlled Drug Release

The use of nanotechnology in drug delivery is a rapidly expanding field, recent research has focused on developing structurally stable, biocompatible, and nontoxic drug delivery systems that are able to deliver a relatively large amount of drug molecules and targeted controllable release. Not only because of specific surface area of the multifunctional inorganic nanoparticles is big, which is easy to surface modification. But also it has unique optical, electrical, magnetic, microwave absorpting properties, which are suitable for used as a carrier of antitumor drug molecules. It is beneficial to improve the therapeutic effect of antitumor drug and reduce the side effects. For cancer therapy, multifunctional inorganic nanoparticles show obvious advantages over other nanoparticulate drug delivery systems.In this paper, We were prepared core-shell structure nanomaterials based on Fe3O4@ZnO with magnetic and microwave thermal response properties, and further coated with mesoporous materials and fluorescent materials, to obtain a new nanocarrier possessing multifunction of targeting delivery, tracking of fluorescence imaging and controlling drug release. Through modification on the surface of a mesoporous with thermally responsive polymer, and then etoposide (VP16) as a template drugs to equip the multifunctional nanocarriers with drug loading through hydrogen bonds; Finally, using the nanocarrier of the thermally responsive characteristics of the microwave, by microwave irradiation to heating the nanocarrier in order to achieve the purpose of the microwave response of controlled drug release. That is building a magnetic targeted, drugs loading by mesoporous, microwave heating controlled drug release of new multifunctional inorganic nanocarrier. The main works and results were listed as follows:(1) Fe3O4@ZnO nanoparticles with magnetic and excellent microwave thermal response properties have been successfully prepared using hydrothermal method and homogeneous precipitation method. In the experiments the influences of surfactants and precipitant on the nanoparticulates products were discussed. Finally, the prepared Fe3O4 and Fe3O4@ZnO nanoparticles have uniform particle size with better morphology and dispersion. Further study of magnetic and microwave thermal response properties of synthesized nanoparticles found that the prepared Fe3O4@ZnO nanoparticles have a strong paramagnetic and good microwave thermal response properties. This study laid the foundation for the next step in the development of drug nanocarrier.(2) We have demonstrated a successful synthesis of multifunctional Fe3O4@ZnO@mSiO2 core-shell structured nanocomposites by combining the hydrothermal method, homogeneous precipitation method, and sol-gel process. The as-prepared core-shell structured material possesses a high magnetization saturation value (56.8 emu/g), high surface area (643.9 m2/g), large accessible pore volume (0.32 cm3/g) and excellent microwave thermal response properties, and by etoposide (VP16) as a template drugs to studied its drug loading, targeting and controlled release of microwave Stimulus. For microwave triggered drug release, the VP16 release of over 85% under microwave discontinuous irradiation outclass the 14% within 10 h only stirring release, that would be very promising for in vivo biomedical drug targeting and controlled drug release system using microwave.(3) An efficient nanoparticle was elaborately fabricated by mesoporous Gd2O3:Eu shell with magnetic Fe3O4 core and ZnO interlayer with a core-shell structure prepared by a simple process. The ZnO shells can effectively absorb and convert microwave to heat upon irradiation with microwaves, and mesoporous Gd2O3:Eu shell not only can increase the efficiency of drug loading, but also can be real-time monitor in vivo fluorescence imaging, and supporters to conjugated thermally responsive polymer poly[(N-isopropylacrylamide)-co-(methacrylic acid)] (P(NIPAm-co-MAA)) as microwave stimulus gatekeepers. The multifunctional nanocarrier provides large accessible pore volume for the adsorption of drug molecules, and has a high magnetization saturation value for drug targeting under an external magnetic field. Microwave irradiation results in P(NIPAm-co-MAA) shrinks to a smaller volume and exposes the pores of mesoporous luminescent shell, realizing the triggered release of entrapped etoposide (VP16) drug. In vitro drug loading and controlled release of microwave research shows that it is a promising drug nanocarrier for remote-controlled drug release systems, and is expected to further applied in the clinical treatment of cancer.