Study On Redox-responsive Mesoporous Silica-coated Gold Nanorods Composite Particles For Combination Chemotherapy And Photothermal Therapy Ofbreast Cancer

With the increasing incidence and mortality year by year,cancer is becoming the leading cause of death and major public health problems in China.Among these,breast cancer is the most common type of cancer in female patients.As the rapid development of nanotechnology bringsnew hope for cancer treatment,efficient intelligent drug delivery system has receivedmain attention in related fields.As for cancer therapy,strategy of combination therapy would realize better clinic curative effect.Owing to their strong plasmon resonance,the long plasmon resonance of gold nanorods could efficiently convert photon energy into heatto kill tumor cells.On the other hands,due to their good biocompatibility,ordered mesoporous structures,high surface areas and a large amount of active hydroxyl groups,mesoporous silicananoparticles are favorable for efficient drug loading and subsequent chemistry modification.To achieve the goal of combinationchemotherapyand photothermal therapy(PTT)against tumors,in this study,we fabricated a nanocarrier based on mesoporous silica-coated gold nanorod.Redox-responsive disulfide was used to graft cytochrome Cwhich serving as end-capping agent.UV-visible near-infrared absorption spectroscopy,particle size statistics and photothermal conversion experiments revealed that gold nanorods with the desired aspect ratiowere synthesized.Transmission electron microscopy,Fourier transform infrared spectroscopy,thermogravimetric analysis and in vitro release tests proved that we successfully constructed a redox responsive mesoporous cilica coated gold nanorod drug delivery system for DOX loading,which was end-capped by cytochrome C.Cell transmission electron microscopy and confocal laser scanning microscopy observations demonstrated that the as-synthesized drug delivery system could be endocytosed efficiently by tumor cells.The CCK-8 assay and confocal laser scanning microscopy confirmed that the drug delivery system hadstrong potential for the inhibition of tumor cells growth on cell level.In vivo thermal imaging suggested that nanocarriers injected through tail vein could largely accumulate attumor site and near-infrared(NIR)laser irradiation could realize photothermal tumor therapy.In vivo experiments(tumor volume,TUNEL and HE staining)suggested that the drug delivery system could efficiently inhibited tumor growth,while without obvious toxic side effects.This study provides new nanocarrier for combination tumor therapy and scientific proof for developing related drug delivery systems.