Research On Preparation And Function Of PH Sensitive Penetrating Nanoparticles

Purpose:First,pH sensitive penetrating nanoparticles were prepared to study the mucus penetration and distribution in mucosal tissue.Then,based on the carrier,multiple oil soluble nanogold particles were loaded to further study the radiation sensitization effect on tumor cells.Method:Amphiphilic block copolymers containing pH sensitive hydrazone bonds were prepared and the structures were analyzed by nuclear magnetic resonance hydrogen spectrum.The pH sensitive penetrating nanoparticles were prepared by ultrasonic emulsification and characterized by transmission electron microscope and laser particle size analyzer,and the biosafety was evaluated by thiazole blue colorimetry and hematoxylin-eosin staining.The retention and distribution of fluorescent dye Cy5.5 labeled pH sensitive penetrating nanoparticles in mucosal tissue were observed by living imager and fluorescence microscope.Multiple oil soluble nanogold particles were loaded to prepared multi-loaded nanoparticles,and the radiation sensitization effect of multi-loaded nanoparticles on tumor cells was evaluated by thiazole blue colorimetry.Results:1.The structure of the reaction intermediates and the amphiphilic block copolymers was analyzed by hydrogen nuclear magnetic resonance,demonstrating that the amphiphilic block copolymers containing pH sensitive hydrazone bonds were successfully synthesized.2.The pH sensitive penetrating nanoparticles were prepared by ultrasonic emulsification.The particle size was about 92 nm,the hydration particle size was concentrated at 134 nm,the surface potential was-3.52±0.76 mV,and it had good response to acidic environment.3.The toxicity of pH sensitive penetrating nanoparticles was evaluated by thiazole blue colorimetry and hematoxylin-eosin staining,demonstrating that pH sensitive penetrating nanoparticles have good biosafety both at the cellular level andtissue level.4.The fluorescent dye Cy5.5-labeled pH sensitive penetrating nanoparticles were injected into the mouse reproductive tract,and the change of the fluorescence intensity of the mouse reproductive tract was observed by living imager.The results showed that the pH sensitive penetrating nanoparticles can effectively extend the retention time of nanoparticles in mucosal tissue.5.The fluorescent dye Cy5.5-labeled pH sensitive penetrating nanoparticles were injected into the mouse reproductive tract,and the distribution in mouse reproductive tract was observed by fluorescence microscope.The results showed that the pH sensitive penetrating nanoparticles not only had good mucus penetration,but also effectively improved the endocytic efficiency of nanoparticles in tissue.6.The oil soluble nanogold particles were successfully prepared,the particle size was relatively uniform and the dispersion was good.The particle size was about 4 nm and there was an ultraviolet absorption peak at 520 nm.7.Multi-loaded nanoparticles were successfully prepared,co-cultured with HeLa cells and irradiated with different doses of X-rays,and the radiation sensitization effect of multi-loaded nanoparticles on tumor cells was evaluated by thiazole blue colorimetry.The results showed that the multi-loaded nanoparticles could effectively improve the sensitivity of tumor cells to radiation and enhance the killing effect on tumor cells.Conclusion:The pH sensitive penetrating nanoparticles prepared in this study have relatively uniform particle size and good dispersibility,and have good biosafty.The experimental results showed that the pH sensitive penetrating nanoparticles not only have good mucus penetration,but also effectively improve the endocytic efficiency of nanoparticles in tissue.This research solves the conflict between mucus penetration and endocytosis in the application of nanoparticles in mucosal tissue,and provide new ideas for the treatment of mucosal tissue diseases.