Research On The Application Of Graphite Phase Carbon Nitride And Graphene Nanocomposites In The Integration Of Cancer Diagnosis And Treatment

Materials with a graphite-like phase structure are emerging inorganic carbon-based materials in recent years.Non-metallic carbon-based nanomaterials including graphene oxide?GO?and carbon nitride?g-C₃N₄?have been widely used in the fields of catalysis and energy.Nanomaterials with a graphite-like phase structure not only have excellent optical properties,but also have the characteristics of low cost,simple synthetic routes,high biocompatibility,and low cytotoxicity.Therefore,the applications of graphene oxide?GO?and carbon nitride?g-C₃N₄?have gradually expanded to biosensing,fluorescence imaging and cancer treatment.Two forms of graphite phase carbon nitrides—CNQDs and C₃N₄NSs were prepared from the top-down method.Then they self-assembled with curcumin,which has chemotherapeutic function and sonosensitizer effect,to obtain a nano-diagnosis platform that integrates imaging and chemotherapy/sonodynamic synergy.In addition,Photothermal therapy is a traditional method for treating cancer with the effect of completely ablating tumors.Using the GO/BaHoF₅/PEG/AUY 922 nano-composite platform prepared by our group,we have further expanded the studies on its drug release,dual-modality imaging,and photothermal therapy in animal.The full text is divided into five chapters.In the first chapter,the structure and biological applications of graphite-like materials are summarized,the specific principles of sonodynamic therapy and photothermal therapy are introduced,and the research ideas of this paper are proposed.In the second chapter,we prepared bulk carbon nitride,and then prepared carbon nitride quantum dots?CNQDs?by high-temperature oxidation pyrolysis-assisted ultrasonic stripping.Furthermore,CNQDs-CGF nanocomposites were prepared through the hydrophilic-hydrophobic interactions between the components and the coordination of curcumin with Gd³⁺.The loading of curcumin,the magnetic resonance imaging performance,the biological safety,and the effect of chemotherapy/sonodynamic in vitro were studied.On a 0.5 T magnetic resonance imager,the effect of T₁ contrast agent is tested.Hemolysis test,MTT test and LC 50 showed that CNQDs-CGF has good biocompatibility and shows limited cytotoxicity to cancer cells.In the verification of the sonodynamic effect,it was found that CNQDs have good sonodynamic effect and played a synergistic effect with curcumin,which can achieve chemotherapy and sonodynamic synergetic treatment.In Chapter 3,we prepared carbon nitride nanosheets?C₃N₄NSs?starting from bulk carbon nitride.Electron micrographs show that it is uniformly dispersed with a size of about 95 nm.Utilizing the high specific surface area of two-dimensional nanomaterials,curcumin?Cur?was loaded on the surface to achieve synergy between chemotherapy and SDT.Hemolysis experiments and cytotoxicity experiments have proved that materials with inorganic C and N nanostructures as carriers have lower toxicity.Because of the access of Gd³⁺,C₃N₄NSs-CGF has the function of MRI,and it has been confirmed that the material has a certain inhibitory effect on cancer cell.In chapter 4,the GO/BaHoF₅/PEG/AUY 922 prepared by our team in the early stage is further applied at the cell and living level.The drug release behavior was studied under different external environment.At the same time,the changes in imaging and photothermal effects after loading AUY 922 were investigated,and the sensitization effect of AUY 922 on in vivo photothermal therapy was verified.In Chapter 5,the data obtained in this subject are analyzed and summarized.Finally,the application of the obtained nanomaterials in the biomedical field,especially the treatment of cancer,is prospected.