Synthesis Of Magnetic Mesoporous Silica Nanoparticles For Drug Delivery

Cancer is one of the most intractable disease risks for human health, and chemotherapy is one of the effective treatments. Most commonly used anticancer drugs are not specifically toxic to tumor cells tissues, which generate undesirable side effects as a result of their interactions with normal tissues. These toxic side effects hinder their developments and applications. The particle size of nano carriers ranges from10to500nm and drug molecules can be encapsulated in the carrier or absorbed on the surface. Safe and effective targeted drug delivery can be achieved by the combination of targeting molecules with specific receptors on cell surface or addition magnetic field followed by entering into cells via cellular uptake. Thus, nano carriers have special value and significance in drug delivery. Inorganic nanoparticles enjoying such applying in the fields of targeted drug delivery, controlled drug release and reducing side eeffects have become the hot spot of new drug delivery system study in recent years. This thesis is focused on the preparation of magnetic mesoporous silica nanoparticles for drug delivery. Fe3CO4/SiO2and NiFe2O4/SiO2nanoparticles were prepared by sol-gel method, and the products were characterized by using high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), nitrogen adsorption-desorption analysis, vibrating sample magnetometer (VSM) and so on. Fe3O4/SiO2nanoparticles were selected as research models to investigate the drug loading and release experiments. Human lung cancer cells (A549cells) were selected to study the cytotoxicity of Fe3O4/SiO2nanoparticles. The main results are listed as follows:1. MCM-41mesoporous silica nanoparticles were prepared by tetraethyl orthosilicate (TEOS) hydrolysis method with cetyltrimethylammonium bromide (CTAB) as template. The magnetic Fe3O4/SiO4and NiFe2O4/SiO2nanoparticles were synthesized via a sol-gel method by loading Fe3O4and NiFe2O4nanoparticles to mesoporous silica matrix. And the content of magnetic nanoparticles deposited in mesoporous pores could be controlled by changing concentration of precursor. HRTEM observations showed that magnetic mesoporous silica nanoparticles had regular spherical structure and uniform diameter (-85nm). EDS data indicated that the content of magnetic oxide increased with increasing of the concentration of precursor. VSM analysis demonstrated that all the two kinds of magnetic mesoporous silica nanoparticles exhibited approximate superparamagnetic behavior. Nitrogen adsorption-desorption analysis showed that magnetic mesoporous silica nanoparticles had large surface area, which provied a good capability for loading drug molecules.2. Fe3O4SiO2nanoparticles were selected for loading anticancer drug doxorubicin hydrochloride (DOX). The in vitro drug loading experiments of DOX showed Fe3O4SiO2nanoparticles had a high drug loading content (6%) and encapsulation efficiency (90.5%). The controlled drug release behavior was performed in different pH values and external magnetic field. The results indicated that DOX@Fe3O4/SiO2nanoparticles could release the drug for a sustained period of time, and the release behavior was influenced by both pH values and magnetic field, which low pH values and external magnetic field could promote the drug release.3. A549cells were selected to investigate the cytotoxicity of Fe3O4SiO2nanoparticles by MTT assay, the results indicated that Fe3O4/SiO2nanoparticles showed a concentration-dependent cytotoxicity. The cell survival rate was still about70%when the concentration of Fe3O4SiO2nanoparticles up to800μg/mL for48h. Additional, the influence of magnetic field on cytotoxicity’was also investigated. These results showed Fe3O4SiO2nanoparticles had a good biocompatibility and magnetic field had no effect to cytotoxicity.