Vernè E, Bosetti M, Brovarone C Vitale, Moisescu C, Lupo F, Spriano S, Cannas M
Materials Science and Chemical Engineering Department, Polytechnic of Torino, Italy.
Biomaterials. 2002 Aug;23(16):3395-403. doi: 10.1016/s0142-9612(02)00040-6.
The aim of this work was to realise bioactive coatings on full density alpha-alumina substrates. An SiO2-CaO-based glass (SC) and an SiO2-Al2O3-P2O5-K2O-CaO-F--based glass-ceramic (SAF) were used for this purpose. Specifically, SAF is a fluoroapatite containing glass-ceramic and previous studies have shown that it is a highly bioactive biomaterial. Furthermore, these fluoroapatite crystals possess a needle-shaped morphology which mimics that of hydroxylapatite found in human hard tissues, particularly in teeth. SAF is a very viscous glass-ceramic and for this reason an intermediate, less viscous, SC layer was interposed in direct contact with alumina aiming to obtain a good coating adhesion. Moreover, this intermediate layer strongly lowers the Al3+ diffusion and thus minimises both compositional changes in the SAF outer layer and the risk of detrimental modifications of the nature of the crystalline phases. A complete characterisation of the coated samples was performed by means of X-ray diffraction, optical and scanning microscopy. Coating adhesion on alumina was tested by comparative shear tests while biocompatibility was investigated on alumina. bulk SAF and on the realised coatings. For this purpose, cytotoxicity, adhesion and proliferation of human osteoblast-like cells were cultured onto the three materials. Results showed that the interposition of the SC layer was successful in allowing a good softening and spreading of the SAF outer layer and in avoiding the crystallisation of undesired crystalline phases maintaining the good bioactive properties of the bulk one. In vitro results on the coatings showed osteoblast-like cell behaviour similar to bulk fluoroapatite glass-ceramic and better respect to alumina substrates, being a promising index of bone material integration and of its in vivo possible applications.
这项工作的目的是在全密度α-氧化铝基底上实现生物活性涂层。为此使用了一种基于SiO₂-CaO的玻璃（SC）和一种基于SiO₂-Al₂O₃-P₂O₅-K₂O-CaO-F的玻璃陶瓷（SAF）。具体而言，SAF是一种含氟磷灰石的玻璃陶瓷，先前的研究表明它是一种具有高生物活性的生物材料。此外，这些氟磷灰石晶体具有针状形态，类似于在人体硬组织特别是牙齿中发现的羟基磷灰石。SAF是一种非常粘稠的玻璃陶瓷，因此，为了获得良好的涂层附着力，在与氧化铝直接接触的位置插入了一层中间的、粘性较小的SC层。此外，该中间层极大地降低了Al³⁺的扩散，从而使SAF外层的成分变化以及晶相性质发生有害改变的风险降至最低。通过X射线衍射、光学显微镜和扫描显微镜对涂层样品进行了全面表征。通过比较剪切试验测试了涂层与氧化铝的附着力，同时对氧化铝、块状SAF和所制备的涂层的生物相容性进行了研究。为此，将人成骨样细胞的细胞毒性、粘附和增殖情况培养在这三种材料上。结果表明，插入SC层成功地使SAF外层实现了良好的软化和铺展，并避免了不期望的晶相结晶，同时保持了块状材料的良好生物活性。涂层的体外结果显示，成骨样细胞的行为类似于块状氟磷灰石玻璃陶瓷，并且相对于氧化铝基底表现更好，这是骨材料整合及其体内可能应用的一个有前景的指标。
