The Construction Of PH-Responsive Tumor Multi-Modal Synergistic System

With the development of science and technology,especially nanotechnology,many new cancer treatment methods have emerged,such as,photothermal therapy?PTT?,photodynamic therapy?PDT?and so on.These treatment methods have been widely concerned with their advantages of small side effects and small trauma,but the therapeutic effects achieved by a single mode of treatment are limited.Therefore,the thesis uses the characteristics of the slightly acidic nature of the tumor microenvironment,combined with photothermal therapy and photodynamic therapy,to construct a multi-mode synergistic therapeutic nanosystem for tumor micro-acid environment response,as follows:1.The construction and properties of pH-responsive MoS₂@PEI/DOX/MB@ZnO nanosystemThe nanosystem consists of MoS₂,doxorubicin?DOX?,methylene blue ?MB?and ZnO quantum dots.Among them,MoS₂ is used as the drug carrier and the photothermal conversion material.The photosensitizer MB produces the singlet oxygen with strong oxidation under light conditions.When the nanosystem reaches the tumor area,the ZnO quantum dots respond to the acidic nature of the tumor microenvironment,leading to the release specifically of the drug in the tumor area,which can avoid damage to normal tissue cells.The experimental results show that the nanosystem not only has good photothermal performance and pH responsiveness,but also can produce a certain amount of singlet oxygen.The cytotoxicity experiment indicated that the nanosystem has good tumor treatment effect,and the effect of multi-mode synergistic treatment is better than that of single mode treatment.2.The synthesis and properties of pH-responsive Au@MoS₂@PEI/5-Fu/MB@PDA nanosystemThe system encapsulates flower-like MoS₂ on the outer layer of gold nanoparticles to form the photothermal conversion material for photothermal therapy,and then loads the anticancer drug 5-fluorouracil?5-Fu?and the photosensitizer methylene blue?MB?,and finally polydopamine?PDA?is coated on the outermost layer to enhance the biocompatibility of the nanosystem and to control the release of the drug by virtue of its acid dissolution characteristics.The experimental results show that the nanosystem has excellent photothermal performance,singlet oxygen production and obvious pH?5.4 and 7.4?responsiveness,and the controlled release effect of PDA is obvious.Cytotoxicity experiments showed that under light irradiation,PTT,PDT and chemotherapy can synergistically kill tumor cells to achieve the best inhibitory effect,and the effect is better than chemotherapy or PTT or PDT alone.