Study On Rapamycin Bionic Liposome For Vascular Endothelial Injury

Objective: Cardiovascular disease is the leading cause of death worldwide,and atherosclerosis is the most common form of the disease,which can be modeled by destroying the endothelial layer of arteries.In this study,we prepared shell-encapsulated rapamycin nanoparticles using natural cell membrane surface properties and liposome mobility function,in order to construct a novel nanocarrier system with long in vivo circulation time,good biosafety,and multifunctionality to target the site of vascular endothelial injury.Among them,the erythrocyte and platelet membranes retain the surface markers on the original cells,making the nanoparticles cell-mimetic and able to specifically target the atherosclerotic injury site;the liposomes make the fusion process more time-and labor-saving;and rapamycin alleviates the endothelial hyperplasia at the injury site.Mmethods: Rapamycin nanoparticles were prepared by W/O emulsification solvent evaporation method,the preparation process of nanoparticles was optimized by single-factor investigation,and the R-PL@SIR NPs were obtained by extrusion method by coating the erythrocyte membrane,platelet membrane and liposome on the nanoparticles.By measuring particle size,potential,encapsulation efficiency and drug loading,Fourier transform infrared spectroscopy,thermogravimetric analysis,high performance liquid determination,SDS-PAGE gel electrophoresis,X-ray photoelectron spectroscopy and other methods were used to analyze Characterization of RPL@SIR NPs Nanoparticles.Meanwhile,the in vitro hemolysis and in vitro release properties,in vitro cytotoxic effects of the nanoparticles were determined,and finally,the pharmacokinetics and safety in vivo were performed.Results: When the loading ratio was 10:1,the sonication time was 6 min,and the organic solvent was ethyl acetate,the rapamycin nanoparticles had a uniform particle size of 151.9±3.6 nm,the loading capacity was 2.66%,and the encapsulation rate was 83.92%;the R-P-L@SIR NPs had a particle size of165.0 nm,the potential value was-13.7 m V,the loading capacity was 1.89%,and the encapsulation rate was 70.86%.Combined with Fourier infrared spectroscopy,thermogravimetric analysis and SDS-PAGE gel electrophoresis,it was found that R-P-L had the physical properties of erythrocyte membrane,platelet membrane and corresponding liposomes,and R-P-L@SIR NPs were able to retain the surface markers of source cells.In addition,the blank vector was biocompatible in MTT assays,and R-P-L@SIR NPs showed concentration-dependent inhibition of HVSMC and RAW264.7 cell proliferation.Compared with SIR NPs,R-P-L@SIR NPs were better able to target LPS-activated HVSMC and escape the recognition effect of macrophages;were able to reduce the production of ROS and NO after activation;had a more pronounced inhibitory effect on HVSMC migration in the scratch assay;and the circulation time of R-P-L@SIR NPs in mice reached48 h,which was four times longer than that of the SIR NPs group.Treatment of SD rats with carotid artery injury was studied.Blood tests and other indices indicated that R-P-L@SIR NPs had good biosafety and no significant longterm toxic effects.Conclusion: We have developed a biomimetic nanosystem RPL@SIR NPs that can effectively target the vascular injury site and reduce intimal hyperplasia after injury.Taking advantage of the long circulation of red blood cells and the properties of platelets to target damaged blood vessels,we wrapped fusion membranes containing surface markers onto rapamycin nanoparticles that can inhibit intimal hyperplasia,while adding liposomes to increase the membrane fluidity of the extrusion process and less preparation resistance.Experiments have proved that R-P-L@SIR NPs has good biosafety,can prolong the drug circulation time in vivo,is expected to improve the accumulation of SIR in vascular injury sites,inhibit intimal hyperplasia,and thus treat cardiovascular diseases.