Development of novel types of bone-like polymer-ceramics composites using self-organized patterns

本课题旨在为具有三维层次结构的聚合物-陶瓷复合材料的制备和新型生物活性材料的开发提供新途径。本项目的成果分为两部分；以凝胶基质中无机晶体的自组织空间模式为模型研究各种实用材料，利用凝胶基质中的空间模式制备层次结构和纳米结构的羟基磷灰石及其复合材料。在本项目的第一部分中，我们发现凝胶基质中质量输运的控制以及有机分子在无机晶体特定表面的特异性吸附是无机晶体自组织空间格局的重要因素。此外，无机晶体与有机胶凝剂之间的强相互作用产生了从纳米到宏观的层次结构。这些发现对于具有三维结构的新型有机-无机复合材料的更多合成是有效的，因为天然生物矿物也由类似于人工系统的纳米级构建块组成。在该项目的第二部分，我们开发了一种新型羟基磷灰石-聚合物复合材料，具有与天然骨相似的分层组织结构。反应条件成功地控制了羟基磷灰石的宏观周期结构，使其从层状结构转变为细胞多孔结构。层压hap -聚合物复合材料具有成为新型生物相容性材料的潜力，因为它们的机械性能与天然骨相似。本研究还提供了另一种制备途径，即通过前驱体晶体的拓扑转变来形成层次结构。通过对含有明胶分子的磷酸二钙脱水进行拓扑过渡，成功制备了新型纳米结构和纳米纤维型羟基磷灰石。通过与明胶分子的特异性相互作用，制备了纳米结构磷酸二钙脱水制备的纳米羟基磷灰石，形成了约20 nm取向框架的纳米羟基磷灰石和沿c轴细长的纳米纤维状羟基磷灰石，直径约50 nm。纳米羟基磷灰石的层次结构提供了高比表面和宏观孔隙，将适用于各种生物医学应用。分层多孔羟基磷灰石结构可作为吸附剂和组织工程的支架。少

This research project aimed proposal of novel routes for preparation of polymer-ceramic composite materials having three-dimensionally hierarchical structures and development of new types of bioactive materials. The results of this project is categorized into two parts ; study of self-organized spatial pattern of inorganic crystals in gel matrix as model cases for various practical materials and preparation of hierarchical and nanostructures hydroxyapatite and its composite materials using the spatial patterning in gel matrix.In part I of this project, we found that the control of mass transport in gel matrix and the adsorption of organic molecules specific on specific surfaces of inorganic crystals the essential factors for the self-organized spatial patterns of inorganic crystals. Moreover, the strong interaction between inorganic crystals and organic gelling agents produced hierarchically organized architecture from nano to macroscale. These findings are effective in the controlled … More synthesis of new types of organic-inorganic composite having three-dimensional structures because natural biominerals are also composed of nanoscale building blocks similar to the artificial system.In part II of this project, we developed a new type of hydroxyapatite-polymer composite having a hierarchically organized architecture similar to that of natural bone. The macroscopic periodic structure of HAp was successfully controlled from laminated layers to a cellular porous form by the reaction condition. The laminated HAp-polymer composites have potential for new types of biocompatible materials, because their mechanical properties are similar to those of natural bone. This study also provided another preparation route through the topotactic transition of precursor crystals for the formation of a hierarchical architecture. Novel types of nanotextured and nanofibrous hydroxyapatite were successfully produced through the topotactic transition of dicalcium phosphate dehydrate containing gelatin molecules. Nanotextured hydroxyapatite with an oriented framework of ca. 20 nm grains and nanofibrous hydroxyapatite elongated along the c axis with a diameter of ca. 50 nm were formed from nanostructured dicalcium phosphate prepared by dehydration through the specific interaction with gelatin molecules. The hierarchical architectures of the nanostructured hydroxyapatite providing a high specific surface and macroscopic pores would be applicable for various biomedical applications. The hierarchical porous hydroxyapatite architectures could be useful as an adsorbent and as a scaffold for tissue engineering. Less