Yamada A, Suzuki D, Shibata Y, Kamijo R, Miyazaki T
Department of Conservative Dentistry, Division of Biomaterials & Engineering, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555,
Eur Cell Mater. 2015 May 20;29:290-302. doi: 10.22203/ecm.v029a22.
Anodically oxidized titanium surfaces, prepared by spark discharge, have micro-submicron surface topography and nano-scale surface chemistry, such as hydrophilic functional groups or hydroxyl radicals in parallel. The complexity of the surface characteristics makes it difficult to draw a clear conclusion as to which surface characteristic, of anodically oxidized titanium, is critical in each biological event. This study examined the in vitro biological changes, induced by various surface characteristics of anodically oxidized titanium with, or without, release of hydroxyl radicals onto the surface. Anodically oxidized titanium enhanced the expression of genes associated with differentiating osteoblasts and increased the degree of matrix mineralization by these cells in vitro. The phenotypes of cells on the anodically oxidized titanium were the same with, or without, release of hydroxyl radicals. However, the nanomechanical properties of this in vitro mineralized tissue were significantly enhanced on surfaces, with release of hydroxyl radicals by oxidation effects. In addition, the mineralized tissue, produced in the presence of bone morphogenetic protein-2 on bare titanium, had significantly weaker nanomechanical properties, despite there being higher osteogenic gene expression levels. We show that enhanced osteogenic cell differentiation on modified titanium is not a sufficient indicator of enhanced in vitro mineralization. This is based on the inferior mechanical properties of mineralized tissues, without either being cultured on a titanium surface with release of hydroxyl radicals, or being supplemented with lysyl oxidase family members.
通过火花放电制备的阳极氧化钛表面具有微米-亚微米级表面形貌和纳米级表面化学性质，例如平行排列的亲水性官能团或羟基自由基。表面特性的复杂性使得难以明确得出阳极氧化钛的哪种表面特性在每个生物学事件中起关键作用的结论。本研究考察了阳极氧化钛的各种表面特性在有或没有向表面释放羟基自由基的情况下所诱导的体外生物学变化。阳极氧化钛增强了与分化成骨细胞相关的基因表达，并在体外增加了这些细胞的基质矿化程度。阳极氧化钛表面上的细胞表型在有或没有释放羟基自由基的情况下是相同的。然而，通过氧化作用释放羟基自由基的表面上，这种体外矿化组织的纳米力学性能显著增强。此外，在裸钛上骨形态发生蛋白-2存在的情况下产生的矿化组织，尽管有成骨基因表达水平较高，但纳米力学性能明显较弱。我们表明，改性钛上成骨细胞分化增强并非体外矿化增强的充分指标。这是基于矿化组织的力学性能较差，无论是在释放羟基自由基的钛表面上培养，还是补充赖氨酰氧化酶家族成员。
