One-step Fabrication Of A Multifunctional PLGA-HMME-DTX@MnO₂ Nanoparticle For Enhanced Chemo-sonodynamic Combined Tumor Treatment

The implementation of the sonodynamic-chemotherapy combination relies on the separate implementation of sonodynamics and chemotherapy,or just the simple splicing of the delivery system of the sonosensitizer and the chemotherapeutic drug carrier.The operation is cumbersome and the temporal and spatial synchronization is not good.Some delivery systems have many preparation steps,complex structure and poor stability,which increase the difficulty of implementation.Currently,tumor tissue hypoxia,acidic microenvironment,and higher levels of hydrogen peroxide and reduced glutathione limit multiple antitumor therapies.Therefore,there is an urgent need to develop a multifunctional integrated nano-preparation system with simple preparation method,concise structure,high safety,tumor targeting and improvement of tumor tissue hypoxia and other limitations.The practicability and feasibility of anti-tumor in development,improving the hypoxic microenvironment while enhancing the synergistic effect of sonodynamic-chemical combination therapy.A new preparation technology,flash nanoprecipitation has the advantages of integrated preparation of multi-component nanoparticles,simple operation,and improved operability of combined sonodynamic-chemotherapy treatment.Using the advantages of flash nanoprecipitation to build a multi-component delivery system,manganese dioxide can be introduced.Under the premise of ensuring biological safety,the various properties of MnO₂ can be combined with the tumor microenvironment to increase the oxygen production of tumor tissue and improve the tumor.Hypoxic microenvironment further improves the anti-tumor efficiency of the combination of sonodynamic-chemotherapy.Based on the above,in this study,The PLGA-HMME-DTX@MnO₂multifunctional nanoparticle with metal oxide manganese dioxide particles distributed on the surface of the nanocarrier and the sonosensitizer hematoporphyrin monomethyl ether and the chemotherapeutic drug docetaxel encapsulated inside was constructed.In addition,its pharmacy characterization and anti-tumor effect in vivo and in vitro were investigated.The specific contents are as follows:1.Multifunctional nanoparticles were successfully prepared by flash nanoprecipitation and characterized.The nanoparticles are small in size,spherical in appearance,good in dispersibility and stability,and can achieve high-efficiency drug release in the acidic environment of tumors with ultrasound;The hematoporphyrin monomethyl ether and the chemotherapeutic drug docetaxel were successfully loaded into the multifunctional nanoparticles;the x-ray electron spectroscopy of the PHD@MnO₂ multifunctional nanoparticles showed that Mn was in the+4 valence state,supplemented by the infrared spectrum,The TEM topography shows that the flash nanoprecipitation technique can successfully introduce manganese dioxide particles on the surface of nanocarriers;PHD@MnO₂ multifunctional nanoparticles have excellent singlet oxygen and hydroxyl radical generation ability.2.Evaluation of the intracellular behavior and in vitro anti-tumor effects of PHD@MnO₂multifunctional nanoparticles using MCF-7 breast cancer cells as a model.After optimization of ultrasonic conditions,the optimal ultrasonic treatment conditions of PHD@MnO₂ multifunctional nanoparticles were found to be 3 minutes,1.75 W/cm²,and the ability to generate singlet oxygen was the strongest under these conditions.The enzymatic pathway is taken up and its uptake mode is time-dependent;the higher the content of manganese dioxide in PHD@MnO₂ multifunctional nanoparticles,the lower the level of reduced glutathione in breast cancer cells,which proves that manganese dioxide plays an important role in tumor regulation played an important role in the microenvironment.3.Evaluation of the in vivo tumor treatment effect and safety and the expression of hypoxia-inducible factor（HIF-1α）in tumor tissue of PHD@MnO₂ multifunctional nanoparticles taking S180 tumor-bearing mice as a model.The study found that the PHD@MnO₂ multifunctional nanoparticles had good tumor targeting,the enrichment in tumor tissue was the largest after intravenous injection and reached the maximum at 12 h,and it had good tumor retention ability.After 24 h of injection It can still maintain a high concentration in tumor tissue,the injection of PHD@MnO₂ multifunctional nanoparticles can significantly inhibit tumor growth.After 14 days of treatment,the tumor volume in the multifunctional nanoparticles group only grows to 2.5 times the initial volume,and The tumor inhibition rate reached 80.25%,which was significantly better than that of other groups.The results of histopathological analysis showed that PHD@MnO₂multifunctional nanoparticles can cause severe tissue damage to tumors and have a good anti-tumor therapeutic effect,but it does not cause obvious damage to other major physiological organs,further confirming the good biocompatibility and safety of multifunctional nanoparticles.After reaching the tumor site,the nanoparticles can block the expression of hypoxia-inducible factor HIF-1αand improve the hypoxic microenvironment of the tumor.In conclusion,the flash nanoprecipitation method was used to prepare multi-component and multifunctional nanoparticles.The construction method of the system provides a new idea.Manganese dioxide was introduced into the combined treatment of sonodynamic-chemotherapy,and the degradability,catalytic properties and strong oxidizing properties of manganese dioxide were cleverly combined with the tumor-specific microenvironment.The decomposition of high-concentration hydrogen peroxide in the environment reduces the level of glutathione,prevents the depletion of reactive oxygen species,improves the hypoxic environment of tumors and the efficiency of sonodynamic-chemotherapy combination therapy,it overcomes the applications of sonodynamic-chemotherapy combination therapy in anti-tumor effectively.