Liu Lumei, Koo Youngmi, Collins Boyce, Xu Zhigang, Sankar Jagannathan, Yun Yeoheung
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. 2017 Aug 10;12(8):e0182914. doi: 10.1371/journal.pone.0182914. eCollection 2017.
Magnesium (Mg)-based stents are extensively explored to alleviate atherosclerosis due to their biodegradability and relative hemocompatibility. To ensure the quality, safety and cost-efficacy of bioresorbable scaffolds and full utilization of the material tunability afforded by alloying, it is critical to access degradability and thrombosis potential of Mg-based alloys using improved in vitro models that mimic as closely as possible the in vivo microenvironment. In this study, we investigated biodegradation and initial thrombogenic behavior of Mg-based alloys at the interface between Mg alloys' surface and simulated physiological environment using a microfluidic system. The degradation properties of Mg-based alloys WE43, AZ31, ZWEK-L, and ZWEK-C were evaluated in complete culture medium and their thrombosis potentials in platelet rich plasma, respectively. The results show that 1) physiological shear stress increased the corrosion rate and decreased platelets adhesion rate as compared to static immersion; 2) secondary phases and impurities in material composition induced galvanic corrosion, resulting in higher corrosion resistance and platelet adhesion rate; 3) Mg-based alloys with higher corrosion rate showed higher platelets adhesion rate. We conclude that a microfluidic-based in vitro system allows evaluation of biodegradation behaviors and platelets responses of Mg-based alloys under specific shear stress, and degradability is related to platelets adhesion.
镁（Mg）基支架因其可生物降解性和相对血液相容性而被广泛研究以缓解动脉粥样硬化。为确保生物可吸收支架的质量、安全性和成本效益，并充分利用合金化提供的材料可调性，使用尽可能接近体内微环境的改进体外模型来评估镁基合金的降解性和血栓形成潜力至关重要。在本研究中，我们使用微流体系统研究了镁基合金在其表面与模拟生理环境之间的界面处的生物降解和初始血栓形成行为。分别在完全培养基中评估了镁基合金WE43、AZ31、ZWEK-L和ZWEK-C的降解性能，并在富血小板血浆中评估了它们的血栓形成潜力。结果表明：1）与静态浸泡相比，生理剪切应力提高了腐蚀速率并降低了血小板粘附率；2）材料成分中的第二相和杂质引发了电偶腐蚀，导致更高的耐腐蚀性和血小板粘附率；3）腐蚀速率较高的镁基合金显示出更高的血小板粘附率。我们得出结论，基于微流体的体外系统允许在特定剪切应力下评估镁基合金的生物降解行为和血小板反应，并且降解性与血小板粘附有关。
