Watanabe Junji, Akashi Mitsuru
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
J Biomater Sci Polym Ed. 2008;19(12):1625-35. doi: 10.1163/156856208786440505.
We report here anisotropic hydroxyapatite (HAp) formation inside an agarose gel using an electrophoretic approach and an alternate soaking process. Effective ion migration is shown to be crucial to integrate hydrogel with biominerals, for example, calcium carbonate and HAp. Calcium and phosphate ions easily migrated into the gel interior from ionic solutions when an electric field was applied to both terminals of the gel. The time to reach complete biomineral formation was only 3 min. In this process, roughly 75-300 microg of HAp was formed in 1 mg of dry gel. Moreover, we carried out alternate soaking using the resulting materials and further HAp formation was observed (750 microg HAp/mg dry gel). HAp was characterized by infrared spectroscopy and X-ray diffraction, and was then assigned. Moreover, the HAp was formed in an anisotropic manner. First, (210) and (211) were preferentially formed by the electrophoretic approach. Alternatively, (002) and (211) were formed after the alternate soaking process. This result indicated that preparative conditions were shown to be crucial to regulate anisotropic crystal growth and to keep it the major component. In summary, it is considered that anisotropic ion diffusion inside the hydrogel would be the dominant factor by electrophoretic and alternate soaking approaches.
我们在此报告一种利用电泳方法和交替浸泡过程在琼脂糖凝胶内部形成各向异性羟基磷灰石（HAp）的方法。有效的离子迁移对于水凝胶与生物矿物质（如碳酸钙和HAp）的结合至关重要。当在凝胶两端施加电场时，钙离子和磷酸根离子很容易从离子溶液迁移到凝胶内部。达到完全生物矿化形成的时间仅为3分钟。在此过程中，每1毫克干凝胶中大约形成了75 - 300微克的HAp。此外，我们使用所得材料进行交替浸泡，并观察到进一步的HAp形成（每毫克干凝胶750微克HAp）。通过红外光谱和X射线衍射对HAp进行了表征并确定了其结构。此外，HAp以各向异性的方式形成。首先，通过电泳方法优先形成（210）和（211）。另外，在交替浸泡过程后形成了（002）和（211）。该结果表明制备条件对于调节各向异性晶体生长并使其成为主要成分至关重要。总之，认为水凝胶内部的各向异性离子扩散是电泳和交替浸泡方法的主要因素。
