微/纳米结构含锌硅酸钙基涂层成骨性能研究

A Study on Osteogenic Properties of Micro/nanostructured Zinc-containing Calcium Silicate-based Coatings

骨科植入物涂层的表面形貌和化学组成对炎症反应的进程和骨形成的发生都发挥着重要调节作用。为综合利用微/纳米仿生结构和生物活性元素的优势,将含锌(Zn)的纳米结构物质引入到经水热处理后的等离子喷涂硅酸钙(calcium silicate,CS)涂层表面,对所制备涂层的物相组成、表面和截面形貌、比表面积、Zeta电位和生理环境下离子溶出等物理化学性能进行了表征。相比于常规CS涂层,具有微/纳米复合结构的CS和含锌CS涂层拥有更高比表面积和孔容,可吸附更多血清蛋白和纤维连接蛋白,通过刺激细胞内整合素以及下游vinculin和FAK基因表达,提高了骨髓间充质干细胞(BMSCs)铺展能力。涂层中锌的引入进一步提高了其表面BMSCs的增殖能力和与成骨细胞分化相关的基因表达。具有微/纳米复合结构的涂层明显上调了RAW264.7巨噬细胞中M2表型因子(CD206和ARG)基因表达,而涂层中溶出的Zn^(2+)显著提高了RAW264.7细胞中抑炎症因子(IL-1ra和IL10)基因表达,促使其向抑炎症表型转化。骨科植入物涂层表面锌元素和纳米结构的引入有利于创建良好的骨免疫微环境,促进骨形成的发生。

The surface morphology and chemical composition of orthopedic implant coatings play an important role in regulating the process of inflammatory response and the occurrence of osteogenesis.In this paper,to take advantage of biomimetic micro/nano-structures and bioactive elements,zinc-containing nanostructures were introduced onto plasma-sprayed calcium silicate(CS)coatings via hydrothermal treatment.The physical and chemical properties of the as-prepared coatings,such as phase composition,surface and cross-sectional morphology,specific surface area,Zeta potential and ion dissolution under physiological environment,were characterized.Compared with CS coatings,hydrothermally treated CS and Zn-containing CS coatings with higher specific surface area and pore volume adsorbed more serum proteins and fibronectin,which up-regulated the expression levels of integrins,vinculin and focal adhesion kinase and promoted cell spreading of bone marrow mesenchymal stem cells(BMSCs).The introduction of Zn^(2+) into the coating further enhanced the proliferation ability of BMSCs and gene expression associated with osteoblast differentiation.The micro/nanostructured coatings considerably up-regulated the gene expression of M2 phenotypic factors(CD206 and ARG)in RAW264.7 macrophages,and the dissolved Zn^(2+) in the coatings significantly increased the gene expression of antiinflammatory factors(IL-1ra and IL-10)in RAW264.7 cells which may promote the polarization of macrophages towards the anti-inflammatory phenotype.The introduction of Zn element and nanostructures on orthopedic implant coating is beneficial to create a good osteoimmune microenvironment for the osteogenesis.