Macrophage Membrane Functionalized ROS-responsive Nanomedicine For Selectively Inhibiting The Injured Vascular Intimal Hyperplasia

Intimal hyperplasia caused by vascular injury is an important pathological process of many vascular diseases.Improving the therapeutic effect of vascular injury is of great significance to curb the development of occlusive vascular disease.Nanomedicine delivery system has attracted much attention in recent years because of its advantages such as efficient solubilization of drugs,improvement of drug distribution in vivo,targeted delivery and reduction of side effects.However,nanomedicine is considered as"foreign substances"by the immune system because it is difficult to construct an outer surface similar to that of cells in the body.Biomimetic biofilm strategy is a promising means to reduce the clearance rate of nanomedicine in vivo.The circulation time of biomimetic nanomedicine in vivo can be increased by camouflage of nanomedicine through cell membranes derived from"in vivo".Combined with the functional characteristics of cells,targeted therapy and controllable load release can be realized,which can not only improve the therapeutic effect but also improve biosafety.In this study,based on the inflammatory microenvironment of vascular injury site,the high expression of reactive oxygen species（ROS）and the physiological process of intimal hyperplasia mediated by vascular smooth muscle cell proliferation,we designed a kind of anti-proliferation biomimetic nanomedicine（MM@PMR）.The biomimetic nanomedicine can be efficiently recruited by inflammatory environment to achieve targeted drug delivery,while real-time response to high levels of ROS to achieve controllable drug release.Studies have shown that MM@PMR can inhibit intimal hyperplasia while retaining good biocompatibility.The main contents and results of this study are as follows:（1）The nanomedicine（PMR）was synthesized by nano-precipitation method from amphiphilic carrier with ROS response and rapamycin（RAPA）with anti-inflammatory and anti-proliferation effect.Then the macrophage membrane was coated on PMR to form biomimetic nanoparticles（MM@PMR）.¹H-NMR,DLS and TEM confirmed the successful synthesis of MM@PMR.The nanoparticles have uniform particle size,good dispersion and"core-shell"structure.The experiments of drug loading rate and entrapment efficiency show that PMR can effectively realize the solubilization of RAPA.The photography of PMR in ROS environment and the release of MM@PMR in PBS environment（with or without H₂O₂）confirmed that MM@PMR can respond to ROS in pathological microenvironment to accelerate local drug release.SDS-PAGE and WB experiments confirmed that the composition of MM@PMR was similar to that of protocell membrane proteins and the main functional proteins CCR2,integrinα4β1 and CD47 were effectively retained.（2）Macrophage phagocytosis test in vitro confirmed that MM@PMR could evade the clearance of immune system.The phagocytosis of inflammatory endothelial cells in vitro confirmed the targeting effect of MM@PMR on pathological sites.Smooth muscle cell proliferation inhibition test and cell scratch test confirmed that MM@PMR could inhibit the proliferation and migration of vascular smooth muscle cells.Hemolysis test and zebrafish embryo toxicity test showed that the carrier had good biocompatibility.（3）Through the mouse carotid artery injury model,it was confirmed that MM@PMR can effectively inhibit the pathological process of intimal hyperplasia after vascular injury.The results of immunohistochemistry confirmed that MM@PMR could down-regulate the level of inflammation at the pathological site.In vivo targeting experiments confirmed that biomimetic nanoparticles can target pathological sites and reduce liver uptake.Organ HE staining,blood routine and body weight records confirmed that MM@PMR did not bring obvious side effects on the body.