State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050, PR China.
Colloids Surf B Biointerfaces. 2011 Sep 1;86(2):267-74. doi: 10.1016/j.colsurfb.2011.04.006. Epub 2011 Apr 17.
Implant surface topography is one of the most important factors affecting the rate and extent of osseointegration. Randomly micron-roughened surfaces have been documented to support osteoblast adhesion, differentiation, and mineralized phenotype, and thus favoring bone fixation of implants to host tissues. However, few studies have been done yet to investigate whether their effects on osteoblast behaviors can be enhanced by incorporation of nano-scale topographic cues. To validate this hypothesis, zirconia coatings with micron roughness (about 6.6 μm) superimposed by nano-sized grains (<50 nm) were fabricated by plasma spraying. To validate the impact of nano-sized grains, post-treatments of surface polishing (SP) and heat treatment (HT) were performed on the as-sprayed (AS) coatings to change the surface topographies but keep the chemical and phase composition similar. Results of in vitro bioactivity test showed that apatite was formed only on coating surfaces with nano-sized grains (AS coatings), indicating the significance of nano-topographic cues on the in vitro bioactivity. Enhanced osteoblast adhesion and higher cell proliferation rate were observed on coatings with both micron-roughness and nano-sized grains (AS-coatings), compared to coatings with smooth surfaces (SP-coatings) and coatings with only micron-scale roughness (heat-treated coatings), indicating the significant effects of nano-size grains on osteoblast responses. As the micron rough surfaces have been well-documented to enhance bone fixation, results of this work suggest that a combination of surface modifications at both micron and nano-scale is required for enhanced osseointegration of orthopedic implants.
种植体表面形貌是影响骨整合速度和程度的最重要因素之一。已经有文献证明，随机微米粗糙表面有利于成骨细胞的黏附、分化和矿化表型，从而有利于种植体与宿主组织的骨固定。然而，目前还很少有研究探讨纳米级形貌特征的加入是否会增强其对成骨细胞行为的影响。为了验证这一假设，通过等离子喷涂制备了具有微米粗糙度（约 6.6 μm）的氧化锆涂层，并在其上叠加纳米级颗粒（<50nm）。为了验证纳米级颗粒的影响，对喷涂后的涂层进行了表面抛光（SP）和热处理（HT）后处理，以改变表面形貌，但保持化学和相组成相似。体外生物活性测试结果表明，仅在具有纳米级颗粒的涂层表面（AS 涂层）形成了磷灰石，表明纳米形貌特征对体外生物活性的重要性。与具有光滑表面的涂层（SP 涂层）和仅具有微米级粗糙度的涂层（热处理涂层）相比，具有微米粗糙度和纳米级颗粒的涂层（AS 涂层）上观察到增强的成骨细胞黏附和更高的细胞增殖率，表明纳米级颗粒对成骨细胞反应有显著影响。由于微米粗糙表面已被充分证明可以增强骨固定，因此这项工作的结果表明，需要对骨科植入物进行表面形貌在微米和纳米尺度上的双重修饰，以增强其骨整合。
