Department of Bioengineering, University of Pittsburgh, 848 Benedum Hall, 3700 O'Hara Street, Pittsburgh, PA 15213, USA.
Acta Biomater. 2013 Nov;9(10):8534-47. doi: 10.1016/j.actbio.2013.07.001. Epub 2013 Jul 12.
Mg-4 wt.% Zn-0.5 wt.% Zr (ZK40) alloy was studied as a candidate material for biodegradable metallic implants in terms of its biocorrosion resistance, mechanical properties and cytocompatibility. The corrosion characteristics of ZK40 alloy were assessed by potentiodynamic polarization and immersion testing in DMEM+10% FBS solution. Analysis of the degradation characteristics by potentiodynamic polarization measurements shows the corrosion rates of ZK40 alloy in as-cast and solution treatment (T4) condition were slightly higher than those of pure Mg or as-drawn AZ31. Determination of the corrosion rate by the weight loss technique reveals that the as-cast ZK40 resulted in slower degradation than other alloy specimens after 7 days of immersion but exhibited accelerated degradation after 14 and 21 days, respectively. T4-treated ZK40 exhibited stable degradation rates compared to as-cast ZK40 and close to those of pure Mg and AZ31 during immersion testing for 14 and 21 days. In order to examine the in vitro cytocompatibility of ZK40 alloy, live/dead cell viability assay and indirect MTT assay were performed using a murine osteoblast-like cell line (MC3T3). After 3 days of direct culture of MC3T3 on ZK40 alloys the live/dead assay indicated favorable cell viability and attachment. The degradation product of ZK40 also showed minimal cytotoxicity when assessed in indirect MTT assay. The mechanical properties of the as-cast and T4-treated ZK40 alloy were superior to those of pure Mg and comparable to as-drawn AZ31. Solution treatment did not significantly enhance the cytocompatibility and mechanical properties of ZK40 alloy. Overall, the ZK40 alloy exhibited favorable cytocompatibility, biocorrosion, and mechanical properties rendering it a potential candidate for degradable implant applications.
ZK40 镁合金（含 4wt.% 镁、0.5wt.% 锌和 0.5wt.% 锆）因其耐腐蚀性、力学性能和细胞相容性而被研究作为生物可降解金属植入物的候选材料。通过动电位极化和在 DMEM+10% FBS 溶液中的浸泡试验评估了 ZK40 合金的腐蚀特性。通过动电位极化测量分析降解特性表明，ZK40 合金在铸态和固溶处理（T4）条件下的腐蚀速率略高于纯镁或拉伸态 AZ31。通过重量损失技术确定的腐蚀速率表明，铸态 ZK40 在浸泡 7 天后的降解速度比其他合金试样慢，但分别在 14 天和 21 天后的降解速度加快。T4 处理的 ZK40 在 14 天和 21 天的浸泡试验中，与铸态 ZK40 相比表现出稳定的降解速率，并且与纯镁和 AZ31 相近。为了检验 ZK40 合金的体外细胞相容性，采用鼠成骨样细胞系（MC3T3）进行了活/死细胞活力测定和间接 MTT 测定。在 MC3T3 直接培养在 ZK40 合金上 3 天后，活/死试验表明细胞活力和黏附良好。在间接 MTT 测定中，ZK40 的降解产物也显示出最小的细胞毒性。铸态和 T4 处理的 ZK40 合金的力学性能优于纯镁，与拉伸态 AZ31 相当。固溶处理并没有显著提高 ZK40 合金的细胞相容性和力学性能。总的来说，ZK40 合金表现出良好的细胞相容性、耐腐蚀性和力学性能，使其成为可降解植入物应用的潜在候选材料。
