In Vitro Corrosion and in Vivo Response to Zinc Implants with Electropolished and Anodized Surfaces
In Vitro Corrosion and in Vivo Response to Zinc Implants with Electropolished and Anodized Surfaces
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DOI：
10.1021/acsami.9b05370
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发表时间：
2019-06-05
影响因子：
9.5
通讯作者：
Goldman, Jeremy
中科院分区：
文献类型：
--
作者：
Guillory, Roger J., II;Sikora-Jasinska, Malgorzata;Goldman, Jeremy
锌基可生物降解金属在心血管支架和骨科应用中得到了广泛的研究。然而，锌表面特征对不良生物反应的影响尚未得到很好的确立。在此，我们假设金属锌植入物的表面氧化膜特性可能严重影响早期新生内膜的生长和发育。表面的电解抛光已成为金属支架的行业标准，而表面的阳极氧化虽然目前尚未在支架上实施，但可以增加稳定氧化膜的厚度并延迟早期植入物降解。在这项研究中，纯锌样品进行电抛光（EP）和阳极氧化（AD）工程氧化膜具有独特的物理和降解特性，确定由动电位极化，电化学阻抗谱，静态浸泡试验。然后将样品植入成年Sprague-Dawley大鼠的主动脉腔内，以确定表面工程对Zn植入物生物相容性反应的影响。结果发现，在体外腐蚀产生的多孔腐蚀层的EP样品和致密层的AD样品。AD材料更耐腐蚀，而EP表面上观察到局部腐蚀和点蚀。有趣的是，由于表面膜特性导致的局部腐蚀的可变性增加直接转化为体内性能，其中100%的AD植入物但仅44%的EP植入物符合生物相容性基准。总体而言，结果表明，可降解锌上的氧化膜严重影响早期新生内膜进展和可降解锌材料的总体成功。
Zinc (Zn)-based biodegradable metals have been widely investigated for cardiovascular stent and orthopedic applications. However, the effect of Zn surface features on adverse biological responses has not been well established. Here, we hypothesized that a metallic zinc implant's surface oxide film character may critically influence early neointimal growth and development. Electropolishing of surfaces has become the industry standard for metallic stents, while anodization of surfaces, although not practiced on stents at present, could increase the thickness of the stable oxide film and delay early-stage implant degradation. In this study, pure zinc samples were electropolished (EP) and anodized (AD) to engineer oxide films with distinctive physical and degradation characteristics, as determined by potentiodynamic polarization, electrochemical impedance spectroscopy, and static immersion tests. The samples were then implanted within the aortic lumen of adult Sprague-Dawley rats to determine the influence of surface engineering on biocompatibility responses to Zn implants. It was found that in vitro corrosion produced a porous corrosion layer for the EP samples and a densified layer on the AD samples. The AD material was more resistant to corrosion, while localized corrosion and pitting was seen on the EP surface. Interestingly, the increased variability from localized corrosion due to the surface film character translated directly to the in vivo performance, where 100% of the AD implants but only 44% of the EP implants met the biocompatibility benchmarks. Overall, the results suggest that oxide films on degradable zinc critically affect early neointimal progression and overall success of degradable Zn materials.