Surface modification of coronary stents with SiCOH plasma nanocoatings for improving endothelialization and anticoagulation.

The surface properties of intravascular stent play a crucial role in preventing in-stent restenosis (ISR). In this study, SiCOH plasma nanocoatings were used to modify the surfaces of intravascular stents to improve their endothelialization and anticoagulation properties. SiCOH plasma nanocoatings with thickness of 30-40 nm were deposited by low-temperature plasmas from a gas mixture of trimethysilane (TMS) and oxygen at different TMS:O2 ratios. Water contact angle measurements showed that the SiCOH plasma nanocoating surfaces prepared from TMS:O2  = 1:4 are hydrophilic with contact angle of 29.5 ± 1.9°. The SiCOH plasma nanocoated 316L stainless steel (316L SS) wafers were first characterized by in vitro adhesion tests for blood platelets and human umbilical vein endothelial cells. The in vitro test results showed that the SiCOH plasma nanocoatings prepared from TMS:O2  = 1:4 had excellent hemo- and cytocompatibility. With uncoated 316L SS stents as the control, the SiCOH plasma nanocoated 316L SS stents were implanted into rabbit abdominal artery model for in vivo evaluation of re-endothelialization and ISR inhibition. After implantation for 12 weeks, the animals testing results showed that the SiCOH plasma nanocoatings accelerated re-endothelialization and inhibited ISR with lumen reduction of 26.3 ± 10.1%, which were considerably less than the 41.9 ± 11.6% lumen reduction from the uncoated control group.