Preparation And Study Of Silicon Dioxide Nanoparticle For Targeting Thermo-chemo Therapy Of Cancer

Cancer is a serious threat to human health. Because of its high morbidity andmortality, cancer has become another major incentive that affects people’s health inaddition to cardiovascular disease. Though chemotherapy is a cancer treatmenttechnology which has an extensive applicition in clinic, the serious side effects ofchemotherapy drugs has limited their better application. Doxorubicin is an anticancerdrug with broad spectrum which has been widely used in clinic to treat a variety ofcancers, and has achieved very good therapeutic effect. However, serious cardiotoxicityand mutant toxicity of doxorubicin remains to be a serious problem worth to be studied.Photothermal therapy is a new cancer treatment technology which kills cancer cellsthrough converting light energy into heat energy due to the higher temperaturesensibility of cancer cells in tumors with slower blood flow ahd richer blood vesselsthan normal cells. With a good photothermal conversion property, photothermaltherapeutic agent is an auxiliary agent for photothermal therapy which can improve theefficiency of photothermal therapy. Due to the special surface enhanced Ramanscattering caused by surface plasmon resonance, gold nano-shell shows a stronglyadjustable light absorption in the near-infrared region and a higher photothermalconversion efficiency widely useful for photothermal therapy of cancer.Liposome, composed of biological membrane-imitated lipid bilayer structure withgood biocompatibility, has shown a wide range and effective applications in manyrespects such as gene therapy, drug delivery and biological sensors. Cerasome is a newcarrier system derived from liposome. Compared to the conventional liposome,cerasome has a better application in drug delivery, gene therapy due to its better stability,biocompatibility and biodegradability under the acidic environment of the tumor site.In this dissertation, cerasome was developed as a carrier platform which combinesphoto-thermal therapy with chemotherapy of cancer together, and then functionlizedwith the magnetic targeting capability. Isocyanate propyl triethoxy silane （ICPTES） anddoxorubicin were bonded together to form the organic-inorganic composite lipid for theself-assembly of cerasome through the thin-film hydration method with the loading ofmagnetic Fe₃O₄nanoparticles. Finally, a layer of gold nano-shell was grown on thesurface of cerasome, obtaining multifunctional nanoparticles for photothermal therapyand chemotherapy guided by magnetic targeting. A series of characterization includingTEM, FTIR, light-controlled drug release and effects of photothermal therapy were thenconducted. It was confirmed that the nanoparticals had a size of150nm to250nm with a negative potential. Because of the irregular shape, it had a exercellent drug releasecharacterization, which was confirmed by the release test. All results showed that thenanoparticls really had a good photothermal and chemotherapy effect with a wellresponse characteristic of magnetic field showing a potential application prospect.