Synthesis Of Mesoporous Silica And Application In Targeted Drug Carrier For Breast Cancer

Mesoporous silica nanoparticles(MSNs)have attracted more and more researchers' attention because of its high surface area,high stability,various controllable morphology structures and uniform pore size.In this thesis,we mainly described the synthesis and characteristics of a novel hierarchical sieve-like structure of mesoporous silica nanoparticle aggregates(hsMSNAs)and explored a novel theranostic drug delivery system based on radial mesoporous silica which hybridized with multiscale magnetic nanoparticle for MRI-guided and alternative magnetic field(AMF)responsive chemotherapy for breast cancer.In recent years,because the porous silica material has pore structures of different grades,high specific surface area and pore volume,it has great potential application value in the fields of catalysis,adsorption,biomedicine and so on.In this paper,mesoporous silica aggregates(hsMSNAs)with different sieve-like structure have been successfully synthesized by simple centrifugation at room temperature.The results showed that the synthesized hsMSNAs are consisted of 40-100 nm mesoporous silica nanoparticles,different preparation conditions were examined to determine the optimal synthetic process(0.5 mL EDA,standing for 18 h,and centrifuging for 5 min at 15,000 rpm).In addition,the EDA fraction and the standing time of colloidal silica are the key factors in the formation of the morphology and structure for colloidal silica formation are the key factors influencing the hsMSNAs' morphology and structure.What's more,because of the excellent biocompatibility,high drug encapsulation efficiency and sustained release property,we conclude that hsMSNAs have considerable potential as drug delivery systems in the field of nanomedicine.Finally,the formation mechanism of the novel structure aggregates was analyzed.It was considered that the new multi-step sieve structure was formed based on the Kelvin-Helmholtz instability and the soft template method.In view of the superior performance of mesoporous silica as a drug carrier,a novel magnetic response release system for breast cancer based on radial porous mesoporous silica was prepared.Superparamagnetic iron oxide nanoparticles(IONPs)with multiscale sizes were prepared by the hydrothermal method(for larger IONPs,lIO NPs)and thermal decomposition method(for ultrasmall IONPs,uIO NPs).And,amino functionalization was performed on the surface of the lIO NPs,mesoporous silica nanoparticles with radially oriented mesochannels were further in-situ grown onto the surface of lIO NPs and both the uIO NPs and doxorubicin(an anti-cancer drug)can be readily incorporated within the mesochannels.To endow the targeting ability of the as-prepared doxorubicinloaded nano-hybrid,folic acid(FA)was modified onto the surface of the particles.obtained the final IOMSN@uIO(DOX)-FA NPs,and its morphology,physical properties,and in vitro cytotoxicity were studied.Analysis and evaluation of anti-tumor effects of cytotoxicity in vivo,etc.demonstrated that the drug delivery system possessed great potential acting as a MRI-guided stimuli-responsive theranostic platform for effective active targeting chemotherapy of breast cancer.