Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China; The Institute of Biomaterials and Surface Engineering, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China; National Science Foundation Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A & T State University, Greensboro, NC 27411, USA.
Acta Biomater. 2013 Nov;9(10):8678-89. doi: 10.1016/j.actbio.2013.02.041. Epub 2013 Mar 1.
Biodegradable magnesium-based materials have a high potential for cardiovascular stent applications; however, there exist concerns on corrosion control and biocompatibility. A surface-eroding coating of poly(1,3-trimethylene carbonate) (PTMC) on magnesium (Mg) alloy was studied, and its dynamic degradation behavior, electrochemical corrosion, hemocompatibility and histocompatibility were investigated. The PTMC coating effectively protected the corrosion of the Mg alloy in the dynamic degradation test. The corrosion current density of the PTMC-coated alloy reduced by three orders and one order of magnitude compared to bare and poly(ε-caprolactone) (PCL)-coated Mg alloy, respectively. Static and dynamic blood tests in vitro indicated that significantly fewer platelets were adherent and activated, and fewer erythrocytes attached on the PTMC-coated surface and showed less hemolysis than on the controls. The PTMC coating after 16 weeks' subcutaneous implantation in rats maintained ~55% of its original thickness and presented a homogeneously flat surface demonstrating surface erosion, in contrast to the PCL coated control, which exhibited non-uniform bulk erosion. The Mg alloy coated with PTMC showed less volume reduction and fewer corrosion products as compared to the controls after 52 weeks in vivo. Excessive inflammation, necrosis and hydrogen gas accumulation were not observed. The homogeneous surface erosion of the PTMC coating from exterior to interior (surface-eroding behavior) and its charge neutral degradation products contribute to its excellent protective performance. It is concluded that PTMC is a promising candidate for a surface-eroding coating applied to Mg-based implants.
可生物降解的镁基材料在心血管支架应用方面具有很大的潜力；然而，在腐蚀控制和生物相容性方面存在一些问题。本研究对镁（Mg）合金表面的聚（1,3-三亚甲基碳酸酯）（PTMC）侵蚀性涂层进行了研究，探讨了其动态降解行为、电化学腐蚀、血液相容性和组织相容性。PTMC 涂层在动态降解试验中有效地保护了镁合金的腐蚀。与裸镁合金和聚（ε-己内酯）（PCL）涂层镁合金相比，PTMC 涂层合金的腐蚀电流密度分别降低了三个数量级和一个数量级。体外静态和动态血液测试表明，在 PTMC 涂层表面，血小板黏附和激活的数量明显减少，红细胞黏附的数量也较少，溶血程度也较轻。与 PCL 涂层对照相比，在大鼠皮下植入 16 周后，PTMC 涂层仍保持约 55%的原始厚度，呈现均匀平坦的表面，表现出表面侵蚀，而 PCL 涂层则表现出不均匀的整体侵蚀。与对照组相比，在体内 52 周后，涂覆 PTMC 的镁合金的体积减少和腐蚀产物较少。未观察到过度的炎症、坏死和氢气积聚。PTMC 涂层从外到内的均匀表面侵蚀（侵蚀行为）及其带电荷中性的降解产物有助于其优异的保护性能。因此，PTMC 是一种很有前途的应用于镁基植入物的表面侵蚀性涂层候选材料。
