National Science Foundation-Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina Agricultural and Technical State University, Greensboro, North Carolina, United States of America.
FIT BEST Laboratory, Department of Chemical, Biological, and Bioengineering, North Carolina Agricultural and Technical State University, Greensboro, North Carolina, United States of America.
PLoS One. 2018 Oct 10;13(10):e0205611. doi: 10.1371/journal.pone.0205611. eCollection 2018.
Polymeric coatings can provide temporary stability to bioresorbable metallic stents at the initial stage of deployment by alleviating rapid degradation and providing better interaction with surrounding vasculature. To understand this interfacing biocompatibility, this study explored the endothelial-cytocompatibility of polymer-coated magnesium (Mg) alloys under static and dynamic conditions compared to that of non-coated Mg alloy surfaces. Poly (carbonate urethane) urea (PCUU) and poly (lactic-co-glycolic acid) (PLGA) were coated on Mg alloys (WE43, AZ31, ZWEKL, ZWEKC) and 316L stainless steel (316L SS, control sample), which were embedded into a microfluidic device to simulate a vascular environment with dynamic flow. The results from attachment and viability tests showed that more cells were attached on the polymer-coated Mg alloys than on non-coated Mg alloys in both static and dynamic conditions. In particular, the attachment and viability on PCUU-coated surfaces were significantly higher than that of PLGA-coated surfaces of WE43 and ZWEKC in both static and dynamic conditions, and of AZ31 in dynamic conditions (P<0.05). The elementary distribution map showed that there were relatively higher Carbon weight percentages and lower Mg weight percentages on PCUU-coated alloys than PLGA-coated alloys. Various levels of pittings were observed underneath the polymer coatings, and the pittings were more severe on the surface of Mg alloys that corroded rapidly. Polymer coatings are recommended to be applied on Mg alloys with relatively low corrosion rates, or after pre-stabilizing the substrate. PCUU-coating has more selective potential to enhance the biocompatibility and mitigate the endothelium damage of Mg alloy stenting.
聚合物涂层可以在生物可吸收金属支架部署的初始阶段提供临时稳定性，减轻快速降解并提供与周围脉管系统更好的相互作用。为了理解这种界面生物相容性，本研究在静态和动态条件下比较了聚合物涂层镁（Mg）合金与非涂层 Mg 合金表面的内皮细胞相容性。聚（碳酸酯-尿烷）脲（PCUU）和聚（乳酸-共-羟基乙酸）（PLGA）被涂覆在 Mg 合金（WE43、AZ31、ZWEKL、ZWEKC）和 316L 不锈钢（316L SS，对照样品）上，并将它们嵌入微流控装置中，以模拟具有动态流动的血管环境。附着和活力测试的结果表明，在静态和动态条件下，更多的细胞附着在聚合物涂层的 Mg 合金上，而不是非涂层的 Mg 合金上。特别是，在静态和动态条件下，PCUU 涂层表面的附着和活力明显高于 WE43 和 ZWEKC 的 PLGA 涂层表面，在动态条件下也高于 AZ31（P<0.05）。元素分布图显示，PCUU 涂层合金的碳重量百分比相对较高，镁重量百分比相对较低，而 PLGA 涂层合金则相反。在聚合物涂层下观察到各种程度的凹坑，在快速腐蚀的 Mg 合金表面，凹坑更严重。建议在腐蚀速率相对较低的 Mg 合金上或在预先稳定基底后应用聚合物涂层。PCUU 涂层具有增强生物相容性和减轻镁合金支架内皮损伤的更具选择性的潜力。
