Experimental Study On Focused Ultrasound Combined With MnO₂/GOD Loaded Nano-particles For Breast Cancer Therapy

BackgroundTumor has become the second largest disease that endangers human health and life.High Intensity Focused Ultrasound?HIFU?as a new technology of non-invasive tumors treatment,has been used for the treatment of solid tumors?benign and malignant?such as uterine fibroids,liver cancer,breast cancer,pancreatic cancer,prostate cancer and kidney cancer,which has demonstrated excellent effectiveness and safety.It has shown potential application.The development of nanomaterials provides new methods for improving its treatment efficiency.Therefore,the exploration of novel nanomaterials has attracted widespread attention.ObjectiveA nano-particles loaded with MnO₂/GOD was studied for the collaborative focused ultrasound treatment of tumors.PPMG nano-particles are targeted to tumor site via EPR effect.It uses the TME to generate oxygen,to change the acoustic environment of tissues,enhance cavitation effect,thereby improving the treatment efficiency of focused ultrasound.The chain reaction is formed by combining manganese dioxide with GOD to further improve the efficiency of producing oxygen.Methods1.Synthesis and characterization of PPMG Nano-particles:Polyethylene glycol modified with symmetric aromatic diselenides serves as a nanocarrier for delivering MnO₂/GOD,which induces dynamic exchange and recombination of diselenide bonds in the hydrophobic core through visible light to form nuclear cross-linked PPMG nanoparticles.The particle size analyzer is used to detect the particle size and potential of the nano-particles.ICP and UV-Vis were used to test the drug load capacity?LC%?of MnO₂ and GOD,respectively.The dissolved oxygen meter was applied to measure dissolved oxygen concentration in real time to check the ability of MnO₂ to generate oxygen.2.In vitro experimental study:The CCK-8 assay was used to quantitatively analyze the inhibitory effect of PPMG nano-particles on tumor cells.CLSM was used for qualitative analysis of intracellular release and endocytosis of PPMG nano-particles.Flow cytometry is applied to quantitatively analyze the endocytosis of PPMG nano-particles.3.In vivo experimental study:The model of subcutaneous breast cancer xenograft in nude mice was established.Hemolysis experiment was performed to evaluate the biosafety of PPMG nano-particles.The in vivo targeting effects after the injection of PPMG nano-particles into the tail vein was observed by using IVIS imaging system.The antitumor efficacy of focused ultrasound combined with PPMG nano-particles was evaluated by antitumor therapy experiments.Results1.Characterization of PPMG Nano-micelle:A nano-particles loaded with MnO₂/GOD were successfully prepared.The particle size of PPMG nano-particles is 157.7±5.66 nm,and the zeta potential is-4.62±1.03 mV.GOD can catalyze the oxidative decomposition of glucose into gluconic acid and H₂O₂.MnO₂ can consume H₂O₂ to generate O₂,remolding the acoustic environment of tissue.In addition,the production and consumption of O₂ reach equilibrium when the mass concentration ratio of MnO₂ and GOD is 25:1.2.In vitro experimental study:PPMG nano-particles can be effective internalization by tumor cells to release MnO₂.The CCK-8 test results show that PPMG nano-particles have higher tumor cell inhibition ability than the control group.CLSM show that PPMG nano-particles were reduced to generate abundant oxygen in tumor cells.3.In vivo experimental study:PPMG nano-particles show good biological safety.In vivo imaging results show that PPMG has the ability to target in vivo.PPMG nano-particles have significant anti-tumor effects,and focused ultrasound combined with PPMG nano-particles showed better therapeutic effect.ConclusionsA nano-particles loaded with MnO₂/GOD has been successfully constructed for the treatment of breast cancer.The nano-particles exhibit good targeting and biological safety.It has the effect of changing the acoustic environment of tissues and improving the treatment efficiency of focused ultrasound.