Engineering Department, Cambridge University, Cambridge CB2 1PZ, UK.
Acta Biomater. 2011 Oct;7(10):3586-94. doi: 10.1016/j.actbio.2011.06.025. Epub 2011 Jun 21.
Hydroxyapatite-gelatin composites have been proposed as suitable scaffolds for bone and dentin tissue regeneration. There is considerable interest in producing these scaffolds using biomimetic methods due to their low energy costs and potential to create composites similar to the tissues they are intended to replace. Here an existing process used to coat a surface with hydroxyapatite under near physiological conditions, the alternate soaking process, is modified and automated using an inexpensive "off the shelf" robotics kit. The process is initially used to precipitate calcium phosphate coatings. Then, in contrast to previous utilizations of the alternate soaking process, gelatin was added directly to the solutions in order to co-precipitate hydroxyapatite-gelatin composites. Samples were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and nanoindentation. Calcium phosphate coatings formed by the alternate soaking process exhibited different calcium to phosphate ratios, with correspondingly distinct structural morphologies. The coatings demonstrated an interconnected structure with measurable mechanical properties, even though they were 95% porous. In contrast, hydroxyapatite-gelatin composite coatings over 2mm thick could be formed with little visible porosity. The hydroxyapatite-gelatin composites demonstrate a composition and mechanical properties similar to those of cortical bone.
羟基磷灰石-明胶复合材料被提议作为骨和牙本质组织再生的合适支架。由于其低能耗和潜在的能够制造出与它们所替代的组织相似的复合材料，因此人们对使用仿生方法生产这些支架产生了浓厚的兴趣。在这里，对现有的在近生理条件下用羟基磷灰石涂覆表面的交替浸泡工艺进行了改进，并使用廉价的“现成”机器人套件对其进行了自动化处理。该过程最初用于沉淀磷酸钙涂层。然后，与以前交替浸泡工艺的利用方式不同，直接将明胶添加到溶液中，以共沉淀羟基磷灰石-明胶复合材料。通过傅里叶变换红外光谱、扫描电子显微镜、能谱和纳米压痕法对样品进行了研究。交替浸泡工艺形成的磷酸钙涂层具有不同的钙磷比，相应地具有不同的结构形态。即使涂层的孔隙率为 95%，涂层也具有可测量的机械性能，表现出相互连接的结构。相比之下，厚度超过 2mm 的羟基磷灰石-明胶复合涂层几乎没有可见的孔隙。羟基磷灰石-明胶复合材料的组成和机械性能与皮质骨相似。
