Preparation Of Fe₃O₄-Ag Janus Particles Coated With SiO₂ And Study On Apoptosis Of MCF-7 Cells Induced By The DOX-Loaded Particles

Now,breast cancer is one of major malignancies and the prevalence rate gradually increases,expecially amang the youngs.Chemotherapy,as a traditional treatment method,has some disadvantages such as poor selectivity,easy clearance,single function and so on.Therefore,the development of multifunctional materials with high efficiency,low toxicity and integration of treatment and diagnostic functions,has attracted widespread attention.The integration of various functions can be easily realized in Janus particles due to their special asymmetric structure.Mesoporous silica not only has excellent biocompatibility,but also can be modified easily on the surface.Therefore,the asymmetric particles of ferricoferric oxide-silver were prepared by a seed growth method,and then were encapsulated by the silica to form multifunctional nanopartisles(SiO2@Fe3O4-Ag).The nanoparticles were used for loading and controlled release of doxorubicin hydrochloride.In chapter one,the application of metal nanoparticles in tumor therapy and diagnosis was reviewed firstly.And then the advantages and applications of mesoporous silica in drug loading and release were introduced.Thereafter the preparation methods of Janus particles,especially magnetic Janus particles,and their applications in tumor diagnosis and treatment were described.Finally,the purpose and design of this paper were proposed.In chapter two,the Fe3O4-Ag Janus nanoparticles were prepared by the seed growth method in nonpolar solvents and coated by silica.The morphology,composition and surface properties of the Janus nanoparticles were investigated.The Janus particles with a diameter of about 90 nm and good magnetic response were obtained.In chapter three,loading doxorubicin on the particle surface and simulating the drug release were investigated.The encapsulation efficiency and the drug loading efficiency could reach 87.8%and 30.5%.The Janus particles after surface modification had pH sensitivity and the release rates of DOX were 10.0±0.2%and 68.5±8.2%in buffer solutions of pH=7.4 and pH=5.4.The blank Janus particles and drug-loaded Janus particles were respectively co-cultured with MCF-7 cells for 24 h.The Janus particles showed good biocompatibility,drug-loaded particles could effectively inhibit cell growth,and their inhibitory effect was enhanced after 808-nm laser irradiation.In chapter four,the preparation method of SiO2@Fe3O4-Ag nanoparticles and the application of Janus particles were summarized.The applications of the Janus nanoparticles in cancer imaging and targeted therapy were prospected.