Wang Zhen-Lin, Yan Yu-Hua, Wan Tao, Yang Hui
College of Materials Science and Engineering, Chongqing University of Technology, Chongqing, China.
Proc Inst Mech Eng H. 2013 Oct;227(10):1094-103. doi: 10.1177/0954411913493845. Epub 2013 Jul 12.
Surface modification of biomedical magnesium alloy using composite coating shows an attemptable approach for the development of Mg-based biomaterials with excellent cytocompatibility. Hydroxyapatite/collagen composite was preliminarily fabricated by biomineralization, the bioactive poly(l-lactic acid)/hydroxyapatite/collagen composite coatings were spin coated on AZ31 magnesium alloy using poly(l-lactic acid) solution mixed with hydroxyapatite/collagen particles, and the resultant materials and coatings were characterized in structure and related properties; furthermore, the in vitro degradation behavior of modified magnesium alloy in 1.5-fold Hank's solution was investigated. The results show that hydroxyapatite/collagen composite achieved chemical bonding between hydroxyapatite and collagen similar to natural bone; composite coatings on AZ31 magnesium alloy retained the bioactive functional groups of the componential materials and improved the corrosion resistance of Mg alloy; the mass fraction of hydroxyapatite/collagen particles incorporated into the composite affected the porous structure, interfacial adhesion and thus the corrosion resistance of the composite coating due to phase separation as well as volume concentration effects of polymer solution. Composite coatings suppressed the sharp rising of pH value and the released Mg(2+) from substrate to extensive degree, and the degradation behavior of the modified magnesium alloy was supposed to be correlated to microstructure of the coating as well as the synergistic reactions among alkaline- and acidic-degraded products.
采用复合涂层对生物医用镁合金进行表面改性，为开发具有优异细胞相容性的镁基生物材料提供了一种可行的方法。通过生物矿化初步制备了羟基磷灰石/胶原蛋白复合材料，将生物活性聚（L-乳酸）/羟基磷灰石/胶原蛋白复合涂层旋涂在AZ31镁合金上，该复合涂层由聚（L-乳酸）溶液与羟基磷灰石/胶原蛋白颗粒混合而成，并对所得材料和涂层的结构及相关性能进行了表征；此外，还研究了改性镁合金在1.5倍汉克斯溶液中的体外降解行为。结果表明，羟基磷灰石/胶原蛋白复合材料实现了羟基磷灰石与胶原蛋白之间类似于天然骨的化学键合；AZ31镁合金上的复合涂层保留了组成材料的生物活性官能团，提高了镁合金的耐蚀性；由于聚合物溶液的相分离以及体积浓度效应，掺入复合材料中的羟基磷灰石/胶原蛋白颗粒的质量分数影响了复合涂层的多孔结构、界面附着力，进而影响了其耐蚀性。复合涂层在很大程度上抑制了pH值的急剧上升和镁离子从基体中的释放，改性镁合金的降解行为可能与涂层的微观结构以及碱性和酸性降解产物之间的协同反应有关。
