Abstract Magnesium (Mg) and its alloys have received widespread attention as implants for orthopedic surgery due to their degradability and appropriate mechanical properties. However, their poor corrosion resistance may lead to a decline of mechanical properties as well as changes in the surrounding microenvironment, which will eventually lead to their failure as implants. In this work, hyaluronic acid (HYA) was immobilized on AZ31 alloy via a mussel-inspired polydopamine (PDA) anchoring layer. The HYA layer closed the cracks caused by the PDA layer. In vitro corrosion behavior of the PDA/HYA composite coating was investigated via potentiodynamic polarization (PDP) and static immersion assay. The corrosion current density of PDA/HYA coating decreased from 8.48×10−5 A/cm2 to 5.71×10−6 A/cm2. During immersion, no obvious local alkalization was observed. Large amounts of calcium phosphate deposited on PDA/HYA coating, which enhanced the biological activity. MTT experiments show that the MC3T3-E1 cell survival rate of polydopamine coating exceeds 100% after cultivated for 5 days. It was found that the number of cells spreading on the surface of PDA/HYA composite coating was the most after the cell culture directly on the surface.

中文翻译：

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AZ31镁合金聚多巴胺/透明质酸复合涂层的耐腐蚀性和生物相容性

摘要 镁（Mg）及其合金由于其可降解性和适当的机械性能而作为骨科手术植入物受到广泛关注。然而，它们的耐腐蚀性差可能会导致机械性能下降以及周围微环境的变化，最终导致其作为植入物的失败。在这项工作中，透明质酸 (HYA) 通过受贻贝启发的聚多巴胺 (PDA) 锚定层固定在 AZ31 合金上。HYA 层封闭了 PDA 层造成的裂缝。PDA/HYA 复合涂层的体外腐蚀行为通过动电位极化 (PDP) 和静态浸渍试验进行研究。PDA/HYA涂层的腐蚀电流密度从8.48×10-5 A/cm2下降到5.71×10-6 A/cm2。在浸泡过程中，未观察到明显的局部碱化。大量磷酸钙沉积在PDA/HYA涂层上，增强了生物活性。MTT实验表明，聚多巴胺涂层的MC3T3-E1细胞在培养5天后存活率超过100%。发现直接在表面进行细胞培养后，PDA/HYA复合涂层表面铺展的细胞数最多。