Investigation On Drug Delivery System For Self-supplying Oxygen Based On PLGA Nanoparticles Encapsulated Erythrocyte Membrane

Objective:Traditional treatments for cancer,such as chemotherapy,have many side effects,drug resistance and so on.New therapies developed in recent years,such as Sonodynamic Therapy?SDT?,have many advantages and can be used to treat deep tumors.However,in the process of sonodynamic therapy for tumors,the therapeutic effect of sonodynamic therapy is often limited by the hypoxia of the tumor site.In order to solve the above issues,a targeted biological carrier system was constructed,which combines chemical therapy with sonodynamic therapy and loads catalase into the carrier system,so that the carrier system can decompose hydrogen peroxide inside the tumor to produce oxygen and solve the problem of hypoxia at the tumor site.In addition,the structure,morphology,in vitro anti-tumor activity and in vivo pharmacodynamics of the prepared carrier system were investigated.Methods:?1?Preparationandcharacterizationof DOX/CAT@PLGA-RM/HA/HP carrier system.PLGA nanoparticles were prepared.Catalase?CAT?and doxorubicin?DOX?were loaded into PLGA nanoparticles to form DOX/CAT@PLGA mixed solution.DOX/CAT@PLGA-RM/HA/HP drug delivery system was prepared by adding hematoporphyrin?HP?and hyaluronic acid?HA?to the mixed solution of DOX/CAT@PLGA and then were wrapped by a red blood cell membrane?RM?on the outer layer of PLGA nanoparticles via extrusion.The carrier system was characterized by nanometer particle size analyzer and transmission electron microscopy?TEM?.Catalase kit was used to detect the activity of CAT in carrier system,and high performance liquid chromatography?HPLC?was used to detect the entrapment rate and drug release rate of DOX in carrier system.?2?Investigation on Anti-Tumor Activity and Targeting in Vitro.In vitro cell experiments,human breast cancer cells?MCF-7?were used as cell models.The antitumor activity in vitro,cell uptake and sonodynamic production of reactive oxygen species?ROS?of the carrier system were investigated.Inhibition rate of the carrier system on cancer cells was detected by MTT;Fluorescence microscopy was used to qualitatively detect the uptake of the carrier system;Flow cytometry was used to quantitatively detect the uptake of the carrier system by cancer cells;The production of reactive oxygen species in cancer cells under ultrasound conditions was measured by DCFH-DA.?3?In vivo Pharmacodynamics.Study in vivo pharmacodynamics experiment,54 Kunming?KM?mice weighing 18±2 g were subcutaneously inoculated with S180 ascites tumor cells on the right upper extremity to establish a tumor model.The changes of tumors in mice were recorded during treatment by tail vein injection,and the therapeutic effect was tested.According to the weight change of mice and HE staining results of tissue sections,the toxicity of the carrier system was detected.Results:The results of nanoparticle size analyzer and transmission electron microscopy showed that DOX/CAT@PLGA-RM/HA/HP was spherical,with a diameter of 110.26±2.04 nm,a potential of-10.96±1.03 mV.The results of HPLC indicated that DOX was successfully encapsulated into the carrier system with DOX encapsulation efficiency of 90%.Catalase activity was 1000?U/mL?by catalase reagent method.The drug release experiment in vitro showed that the carrier system could release the drug under the co-stimulation of H₂O₂ and US with the rate of86.5%at 48 h.In vitro cell experiments indicated that CAT@PLGA-RM/HA/HP has good biocompatibility.DOX/CAT@PLGA-RM/HA/HP could inhibit the growth of cancer cellsbycombiningsonodynamicswithchemotherapy.The DOX/CAT@PLGA-RM/HA/HP carrier system modified by HA was targeted to cancer cell with uptake efficiency of 96.1%.In vivo pharmacodynamic showed that DOX/CAT@PLGA-RM/HA/HP combined with sonodynamic and chemotherapeutics could significantly inhibit the growth of tumors with the relative rate of 0.90±0.40 for tumor growth and lower than the rate of 8.00±0.60 of blank group.Conclusions:The DOX/CAT@PLGA-RM/HA/HP constructed in the study has tumor targeting and self-supply oxygen to improve hypoxia in sonodynamic therapy,the result in vivo showed it could significantly inhibit the growth of tumor.