Preparation,Characterization And Biocompatibility Of Graphene Oxide Double Layer Drug Coating

Cardiovascular disease is increasingly endangering human health,and there is a growing trend of younger.Vascular stent implantation and other percutaneous coronary intervention can quickly restore the blood supply of ischemic myocardium.They have been widely used in clinical treatment because of high efficiency and minimally invasive,which made them become the most important and effective cardiovascular disease diagnosis and treatment technologies.However,such interventions will cause intimal damage through the extrusion and abrasion to the vessel wall,non-specific inhibition of drug loading and metal stent wire sustained stimulation,and then lead to thrombosis,smooth muscle cells proliferation,in-stent restenosis and late thrombosis.How to balance the anti-proliferation and promote re-endothelialization has become a hot topic in the present studies.In this study,we constructed a new type of graphene oxide(GO)double layer drug coating to achieve anti-proliferation and anti-thrombosis.So we used dopamine to modify 316 L stainless steel,then built anti-proliferative coating,anti-thrombosis and promoting re-endothelialization coating on the surface.The inner layer was coated with GO loaded with docetaxel(DTX),and the outer layer was coated with carboxymethyl chitosan(CMC)loaded with heparin(Hep).This GO double layer drug coating was tested by coating characterization,zebrafish toxicity test,biocompatibility experiments and animal experiments to verify their biosafety,effects of anti-proliferation and anti-thrombosis.Main contents and conclusions of this paper were following:1)Preparation and characterization of GO double layer drug coating.We prepared GO double layer drug coating by the vascular stent ultrasonic atomization micro-drug sprayer CS-Ⅲ(Horizontal speed V1=4mm/s,Spinning speed V2=9r/s,Number of processing works n=25),which was developed by our laboratory.Using scanning electron microscopy and atomic force microscopy detection,we found that the roughness values(Ra)of 316 L stainless steel,DA,GO/DTX and CMC/Hep coatings were 2.203±0.43 nm,3.143±0.81 nm,4.623±1.10 nm,2.771±0.77 nm respectively.The results of water contact angle showed that the GO double layer drug coating had good hydrophilicity.2)Zebrafish toxicity tests of GO double layer drug coating.Through the zebrafish toxicity tests,we found that the GO double layer drug coating had no significant effect on the main physiological indexes of zebrafish,such as the survival rate,hatching rate,and heart rate.We found that the GO double layer drug coating doesn’t cause deformity and organ abnormalities of zebrafish under stereomicroscope.3)Blood compatibility of GO double layer drug coating.The hemolysis test showed that the hemolysis rates of the 316 L stainless steel,DA coating,GO/DTX coating and CMC/Hep were 3.05%,2.73%,3.33% and 1.85% respectively,which were less than 5% of the national standard.Platelet adhesion and morphological detection results showed that the GO double layer drug coating had the best function of antiplatelet adhesion and aggregation,and had little effect on platelet morphology.4)Effects of GO double layer drug coating on smooth muscle cells.Through the cell proliferation experiments and morphological observations,we found that the complete GO/DTX and CMC/Hep coatings could significantly inhibit the proliferation of smooth muscle cells.The cytoskeleton became blurred and irregular.All the results showed that two kinds of coatings could influence not only the proliferation but also the morphology.5)Animal experiment: the implantation of GO double layer drug coating stent into rabbits.GO double layer drug coating stents were implanted into the carotid arteries of rabbits.Compared with the 316 L stainless steel bare stents group,the GO double layer drug coating stents were covered by neointimal,after 4weeks.The endothelial cells were regularly arranged on the surface.We didn’t find any impurities adhesion on them.And the HE staining results showed that there was no intimal endometrial hyperplasia,in-stent restenosis,and thrombosis after the implantation of GO double layer drug coating stents.All the results showed that GO double layer drug coating stents had a good effect on anti-proliferation and anti-thrombosis.