Facile Preparation of Poly(lactic acid)/Brushite Bilayer Coating on Biodegradable Magnesium Alloys with Multiple Functionalities for Orthopedic Application
Facile Preparation of Poly(lactic acid)/Brushite Bilayer Coating on Biodegradable Magnesium Alloys with Multiple Functionalities for Orthopedic Application
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DOI：
10.1021/acsami.7b00209
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发表时间：
2017-03-22
影响因子：
9.5
通讯作者：
Yuan, Guangyin
中科院分区：
文献类型：
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作者：
Lei, Zhang;Jia, Pei;Yuan, Guangyin
近年来，镁及其合金被认为是一种有前途的下一代骨科植入材料，但其腐蚀性差、潜在的细胞毒性以及缺乏有效的药物释放系统等问题限制了其进一步的临床应用，尤其是在感染或肌肉骨骼疾病的局部治疗方面。在这项研究中，我们设计并开发了一种多功能的聚（乳酸）/透钙磷石双层复合涂层的Mg-Nd-Zn-Zr合金，具有高的界面结合强度，旨在提高镁基基板的生物耐腐蚀性和生物相容性，以及进一步纳入局部药物输送的生物功能。该复合涂层由作为药物载体的聚乳酸内层和通过化学溶液沉积产生的透钙磷石外层组成，其中对聚乳酸涂层施加UV照射的简易预处理以促进透钙磷石的异相成核。电化学测量和浸泡试验的体外降解结果表明，复合涂层显著降低了镁的降解。通过细胞活力、粘附和ALP测定对细胞反应进行的系统研究。证实了涂层镁合金对MC 3 T3-E1成骨细胞没有毒性，而是促进细胞附着和增殖，促进成骨分化，显示出优异的生物安全性和生物相容性，并增强了骨诱导潜力。紫外-可见光谱法测定了紫杉醇在复合涂层中的体外释药曲线，结果表明，载药复合涂层具有初始突释缓解和缓释控释的特征。结果表明，聚乳酸/透钙磷石双层涂层对镁合金具有有效的保护作用，增强了镁合金的细胞相容性和生物活性，并具有局部给药的能力，在骨科临床应用，尤其是局部骨治疗方面具有很大的潜力。
Recently magnesium and its alloys have been proposed as a promising next generation orthopedic implant material, whereas the poor corrosion behavior; potential cytotoxicity, and the lack of efficient drug delivery system have limited its further clinical application, especially for the local treatment of infections or musculoskeletal disorders and diseases. In this study, we designed and developed a multifunctional bilayer composite coating of poly(lactic acid)/brushite with high interfacial bonding strength on a Mg-Nd-Zn-Zr alloy, aiming to improve the biocorrosion resistance and biocompatibility of the magnesium-based substrate, as well as to further incorporate the biofunctionality of localized drug delivery. The composite coating consisted of an inner layer of poly(lactic acid) serving as a drug carrier and an outer layer composed of brushite generated through chemical solution deposition, where a facile pretreatment of UV irradiation was applied to the poly(lactic acid) coating to facilitate the heterogeneous nucleation of brushite. The in vitro degradation results, of electrochemical measurements and immersion tests indicated a considerable reduction of magnesium degradation provided the composite coating. A systematic investigation of cellular response with cell viability, adhesion, and ALP assays. confirmed the coated Mg alloy induced no toxicity to MC3T3-E1 osteoblastic cells but rather fostered cell attachment and proliferation and promoted osteogenic differentiation, revealing excellent biosafety and biocompatibility and enhanced osteoinductive potential. An in vitro drug release profile of paclitaxel from the composite coating was monitored with UV-vis spectroscopy, showing an alleviated initial burst release and a sustained and controlled release feature of the drug-loaded composite coating. These findings suggested that the bilayer poly(lactic acid)/brushite coating provided effective protection for Mg alloy, greatly enhanced cytocompatibility and bioactivity, and, moreover, possessed local drug delivery capability; hence magnesium alloy with poly(lactic acid)/brushite coating presents great potential in orthopedic clinical applications, especially for localized bone therapy.