Research On Laser Processing Technology Of MiRNA137 Coronary Stent

Percutaneous coronary intervention(PCI)represented by drug stents has become one of the main clinical treatments for coronary heart disease in recent years,but instent restenosis after surgery is still a clinical problem that needs to be resolved.The use of drug-eluting stents can significantly reduce the rate of restenosis,but there is still a risk of late thrombosis in the stent.Therefore,the development of a new type of stent with good targeting,low toxic and side effects,low restenosis rate and avoiding thrombosis has great theoretical and practical significance.Using laser processing technology to prepare micro-nano structures on the surface of the stent can effectively improve the biocompatibility of the stent and improve the drug loading performance at the same time.Four-beam laser interference processing technology has obtained good theoretical and experimental progress in the preparation of drug-loaded microstructures of coronary stent,and further improving the effect of processing has become a hotspot in recent research.In this thesis,a mutual injection dual-output solid-state laser was used as the light source to construct a mutual injection four-beam interference processing system,and the surface of the coronary stent was micro structured.First,MATLAB was used to simulate the machining process,mainly to simulate the influence of various parameters on the interference results,and to provide a theoretical basis for the interference machining experiment.Afterwards,the processing experiment of the microstructure of the stent surface was carried out.Under the conditions of incident angles of 48.8°,14.5°,and 8.6°,three micro-nano structures with periods of 1.063?m,3.077?m and 5.082?m were obtained.The micro-nano structures prepared by the experiment are consistent with the simulation results.Finally,the drug loading experiment of the stent was carried out.First,the PEGylated liposome was fixed on the surface of the stent by electrophoretic deposition to form a PEGylated liposome-coated stent,and then miRNA137 was embedded in the coating by dip coating and self-assembly to obtain a new type of miRNA137 biomimetic coated coronary stent.In order to test the drug loading and drug release performance of the processed stents,three sets of stents were weighed and put into the blood circulation simulation device.After comparison,the structured stent with the period of 3.077?m has superior adhesion and drug release properties to miRNA137 compared to other structures.The miRNA137 biomimetic coated coronary stent prepared by the experiment has positive significance for inhibiting postoperative restenosis.