Delivery And Antitumor Mechanism Of Apigenin Loaded On Magnetic Fe₃O₄/Fe₂O₃@mSiO₂ Nanocomposites To A549 Cells

Magnetic iron oxide nanoparticles were widely used in the field of biomedicine due to their nano-size effect,high biocompatibility and magnetic response capabilities.In recent years,the application of magnetic iron oxide nanoparticles as the carriers of anti-tumor drugs or diagnostic agent had became a research hotspot.Through the modification of various materials,the targeting effect and drug delivery ability of nanocarriers could be further enhanced,thereby improving the therapeutic effect on tumors and reducing side effects.In this thesis,the preparation and modification methods of magnetic iron oxide nanoparticles were introduced,and their applications in the field of antitumor were summarized.Magnetic Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles were prepared and then modified with SiO₂ and hyaluronic acid?HA?on the surface,the drug apigenin?API?was loaded.The antitumor effect and mechanisms of the new drug carrier was studied in vitro.The main research conclusions were as follows:?1?The magnetic Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles were prepared via rapid-combustion method and characterized by XRD,SEM,TEM,VSM,FTIR,BET,and DLS.The effect of solvent type,solvent volume,calcination temperature,and calcination time on the crystal size and magnetism of the products were investigated.It was determined that absolute ethanol was the most suitable reaction solvent,and as the volume of absolute ethanol increased from 15 mL to 100 mL,the crystal size increased from 26.4 nm to 29.3nm,which had reached the maximum of 30.5 nm when the volume was 30 mL,and the saturation magnetization?Ms?reduced from 57.5 Am²/kg to 5.5 Am²/kg.As the calcination temperature was 400 ^oC,the Ms peaked at the calcination time of 2 h.The average crystal size was increased from 17.2 nm to 49.4 nm as the calcination temperature increased from 200⁷00 ^oC as calcination time maintain at 2 h.When the calcination temperature was 300⁴00 ^oC,the products were typical magnetic Fe₂O₃/Fe₃O₄heterogeneous nanoparticles.As the temperature increased,the Fe₃O₄ proportion in the Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles decreased from 43.5%to 9.6%.?2?The magnetic Fe₂O₃/Fe₃O₄@mSiO₂ nanocomposites with mesoporous silica shell was prepared by an improved Stober method.The average particle diameter was about 150 nm and the specific surface area was 369.6 m²/g.The surface was modified by APTES.API was successfully loaded into the magnetic Fe₂O₃/Fe₃O₄@mSiO₂nanocomposites,and the maximum loading capacity reached 83.9 mg/g.Through the EDC/NHS cross-linking reaction,Fe₂O₃/Fe₃O₄@mSiO₂-NH₂ was successfully connected with hyaluronic acid.It was found that the linking of HA delayed the release of apigenin in vitro and endowed the magnetic drug nanocarrier targeting release capacity in the tumor acidic environment.?3?The biocompatibility of the blank magnetic vector and the cytotoxicity of nanocarrier loaded apigenin were demonstrated by MTT experiments.the magnetic Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles showed different cytotoxicity according to different preparation conditions.Magnetic Fe₂O₃/Fe₃O₄@mSiO₂-HA nanocomposites showed good biocompatibility to A549 cells,PC12 cells and HUVEC cells.It was found that the proliferation of A549 cells could be significantly inhibited by 80?M of API-Fe₂O₃/Fe₃O₄@mSiO₂-HA under the applied of magnetic field,which was stronger than free API at the same dose.Western blot,flow cytometry,and double staining experiments with AO/EB confirmed that the magnetic drug carrier mainly exerted anti-tumor effects by promoting apoptosis.The expression of caspase-3,caspase-8,CytC,Bax was up-regulated and Bcl-2 expression was decreased.The expression level of the cell surface hyaluronic acid receptor CD44 in A549 cells was higher than that of normal cells L-02.The scratch experiment showed that the nanocarrier modified by hyaluronic acid would not cause the tumor cells to accelerate migration.Further research found that API-Fe₂O₃/Fe₃O₄@mSiO₂-HA significantly increased the content of ROS in A549 cells.And ferroptosis might play an essential role in the improved killing effect on tumor cells of magnetic API nanocarrier to free API.