Inhibition of in-stent restenosis after graphene oxide double-layer drug coating with good biocompatibility

In this study, we designed a double layer-coated vascular stent of 316L stainless steel using an ultrasonic spray system to achieve both antiproliferation and antithrombosis. The coating included an inner layer of graphene oxide (GO) loaded with docetaxel (DTX) and an outer layer of carboxymethyl chitosan (CMC) loaded with heparin (Hep). The coated surface was uniform without aggregation and shedding phenomena before and after stent expanded. The coating treatment was able to inhibit the adhesion and activation of platelets and the proliferation and migration of smooth muscle cells, indicating the excellent biocompatibility and antiproliferation ability. The toxicity tests showed that the GO/DTX and CMC/Hep coating did not cause deformity and organ abnormalities in zebrafish under stereomicroscope. The stents with GO double-layer coating were safe and could effectively prevent thrombosis and in-stent restenosis after the implantation into rabbit carotid arteries for 4-12 weeks.