Enhanced corrosion resistance and biocompatibility of Mg-Zn-Y-Nd alloy achieved with APTES pre-treatment for drug-eluting vascular stent application

Abstract

Event Abstract Back to Event Enhanced corrosion resistance and biocompatibility of Mg−Zn−Y−Nd alloy achieved with APTES pre-treatment for drug-eluting vascular stent application Jing Liu1, Tingfei Xi1 and Ming Chen2 1 Peking University, Academy for Advanced Interdisciplinary Studies, China 2 Peking University First Hospital, Cardiovascular Internal Medicine Department, China Bioabsorbable magnesium alloys (Mg) are advantageous in temporary functional implant applications, as they avoid the risks posed by permanent metallic implants. Nevertheless, the over-fast corrosion of Mg alloys under physiological conditions hinders its wider use as medical implants. Here we introduce a convenient one-step process to introduce a cross-linked 3-amino-propyltrimethoxysilane (APTES) silane physical barrier layer on the surface of Mg-Zn-Y-Nd alloys before coating with drug-eluting poly (glycolide-co-lactide) (PLGA) layer loaded with rapamycin. Surface microstructure was characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS). Nano-scratch test verifies the adhesion strength of the PLGA pre-treated with APTES is superior to direct PLGA coating. Electrochemical testing combined with long-term immersion results indicate that the APTES coating results in preferable in vitro anti-corrosion behaviour. Cell morphology and proliferation tests demonstrate that APTES pre-treated Mg-Zn-Y-Nd substrate shows markedly preferable effects for both human umbilical vein endothelial cells (EA. hy926) and vascular smooth muscle cells (VSMC). Furthermore, the in vivo test via implanting APTES pre-treated Mg-Zn-Y-Nd stent to porcine coronary arteries for 6 months confirms benign tissue compatibility with the well re-endothelialized vessel with no sign of obvious thrombogenesis and restenosis. National Basic Research Program of China (Grant No. 2012CB619102); Shenzhen Science and Technology Funding Projects (CXZZ20140730091722497); Shenzhen Special Funds for Development of Strategic Emerging Industries(Project No. JCYJ20130402172)