生物矿物是生物机体的重要组成部分，其中有机模板的指导作用是该类矿物形成的主要特征。在有机模板的指导下，矿物的物相、尺寸、形状、取向、纹理及各组分的浓度均得到精确的控制。骨骼、牙齿、贝壳、珍珠等均为生物矿化的典型产物，矿化晶型专一、结构多样，具有常规复合材料不可比拟的性能优势。因此，有机模板对无机矿物的诱导作用，尤其是有机/无机的界面作用与矿化产物结构之间的关系一直是研究的热点。近年来材料研究者们基于以上的认识在生物仿生材料领域开展了大量有意义的工作，特别是在生物医用材料方面已经取得了长足的进展。本论文在查阅相关文献的基础上，采用基于凝胶模板驱动的原位沉积方法仿生合成了钙盐类复合材料，以多种现代仪器分析手段对不同微观尺度下有机/无机的复合方式、成分的分布、力学性能以及生物有机分子对无机矿物晶体生长的控制行为进行了系统的研究，旨在寻找到合适的有机模板及实验参数条件来调控天然骨的主要无机成分-羟基磷灰石的晶型、粒度、沉淀方式和分散状态进而进行原位仿生合成，以期为合成新型骨缺损修复材料提供有益的启示。具体研究内容如下： 1.采用基于凝胶模板驱动的原位沉积技术分别仿生合成了纳米羟基磷灰石/聚丙烯酸复合物，纳米羟基磷灰石/壳聚糖/柠檬酸复合物，纳米羟基磷灰石/胶原复合物，借助扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线衍射分析(XRD)和傅立叶变换红外光谱(FTIR)对合成的复合材料进行结构和成分性质的表征，采用材料力学试验机对复合体系的力学性能进行测试。结果表明:在无机/无机物复合物的形成过程中，有机水凝胶三维模板对无机矿物晶体的形成具有非常明显的调控作用，三维凝胶网格提供的纳米级隔室化空间，可控制无机粒子的大小和分散度，结合原位复合技术使合成与分散一次完成。原位复合技术生成的纳米第二相呈高度分散态且与基体间的界面无杂质污染，两者之间有理想的原位匹配，能显著改善材料中两相界面的结合状况，使材料具有优良的热力学稳定性；其次，原位复合省去了第二相的预合成，简化了工艺，降低了原材料成本；此外，原位复合还能够实现材料的特殊超微结构设计。 在上述制备的均匀纳米羟基磷灰石/有机高分子水凝胶复合物的基础上，采用我们发展成熟的多孔成形冻干技术，制备了多级多孔组织工程纳米复合支架材料。以此模拟形成骨小梁、小梁间隙和骨内管腔系统，从介观到微观尺度形成多级构造，使其在不同的结构层次均具有类骨仿生特点。采用这种技术制备复合材料，可望显著提高支架材料的生物活性和力学性能。 以人工合成的高分子聚丙烯酸水凝胶为出发点，在解决纳米无机矿物粒子在有机基质中的分散问题的基础上，再进行天然高分子壳聚糖水凝胶的巩固，以及多级多孔复合支架的形成的规律；在与骨组织中有机成分类似的胶原凝胶上，实现了具有大孔-小孔-纳米复合三级构造特征磷灰石/胶原骨组织工程支架材料的制备。研究结果表明有机模板的选择既考虑到各自自身的特点，又相互关联地逐渐向自然骨组织逼近。本研究不但揭示了三维水凝胶有机模板对无机磷灰石矿物的多层次调控规律，为仿生合成骨修复材料拓展了新的视角，也为其它无机/有机纳米复合材料的合成提供了新的思路。 2.分别选择聚丙烯酰胺水凝胶和壳聚糖水凝胶作为有机模板诱导碳酸钙晶体的生成，以扫描电子显微镜(SEM)和透射电子显微镜(TEM)方法用于分析沉淀产物的形貌特征及纳米粒子的聚集行为，X-射线衍射分析(XRD)和傅立叶红外光谱仪(FTIR)用于研究无机矿物的沉淀相成分。结果表明：水凝胶模板的多重调控作用对碳酸钙晶体的生长具有十分明显的调制效果，其3D网格结构作为第一级模板主要起结构框架的作用，而有机高分子中一些带有负电性的基团，如羧基，氨基等则起提供成核位点的第二级模板作用。碳酸钙矿物呈现出明显的粉体自组织多级构造特征。 针对水凝胶有机模板诱导的精细晶体粒子和微晶聚集行为，我们提出了无机晶体的生长模型，以有限长大和有限融合机制较好的解释了从纳米到微米尺度的粉体自组织多级构造的成因。 3.从上述合成得到的纳米羟基磷灰石/高分子水凝胶复合物，以及具有不同多级构造形貌特征的碳酸钙晶体，再对照本课题组前期研究的天然生物矿化材料，如珍珠，贝壳，牙齿等，发现具有多级构造特征的分形结构是它们所具备的共同特征。因此，在本部分研究内容中，首先找出各类生物材料多级构造中存在的自相似性，用分形语言描述，并通过本实验室开发的带分形计算软件的电镜联机图象处理软件测出其分数维，了解分数维与材料自身构造之间的关系，总结出不同材料的分形规律；并在此基础上，讨论了分数维与材料制各条件(温度，时间，浓度，复合方式等)之间的关系，以期通过分形研究来改善材料的性能，表征其构效关系。 关键词：生物矿化 羟基磷灰石(HA) 碳酸钙 有机模板 纳米复合材料 多级构造 原位沉积 模板驱动 分形 均匀分散

 Biological minerals are very important components of organism and high-performance composite materials. Mediated by organic templates, phases、size、 morphology、orientation、texture and content of each component of inorganic minerals can been controlled precisely. Bone、tooth、shell and peal are typical products of biomineralization which have characteristic of single crystalline morphology and various structures, and have better performance than composites prepared by normal methods. So many researches focus on induction effect of organic templates to inorganic minerals, especially relations between interface actions of inorganic/organic phases and structures of products. In recent years, based on above studies, researchers have carried many significant works in the area of biomaterials, and make some great progresses in biomedical materials. Referring to relative literatures, we prepared calcium composite by means of in situ precipitation based on organic hydrogel templates-driven, and composite mode of inorganic/organic phases on different microcosmic scale、distribution of component and mechanical performance were systemically investigated by means of many various modem analysis instrument, the aim of this study is to find a kind of good organic template and suitable experimental parameters to regulated the growth of inorganic minerals —hydroxyapatite which is the main inorganic component of natural bone, and expect to obtain some useful inspiration for the bone repair materials. In this dissertation, the mechanism of biomineralization has been studied systematically by modem instrumental analysis. The main contents of this Ph.D. dissertation are as following: 1.Homogeneous nano-hydroxyapatite/polyacrylic acid composites, nano-hydroxyapatite/chitosan/citric acid composites, nanao-hydroxyapatite/collagen composite were respectively prepared by an approach of in situ precipitation through template-driven. The morphological and componential characteristics of the nanocomposite were performed by means of SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope), XRD (X-Ray Diffraction Analyzer) and FTIR (F), mechanical properties of nanocomposite was characterized by Universal Testing Machine. The experimental results indicate that organic hydrogel template played an obvious mediation effect during the fabrication of inorganic/organic nanaocomposite. The compartment effect from 3D scaffold of hydrogel can control the size and decentralization degree of inorganic particles in organic matrices. The fabrication of nanocomposite and dispersing of hydroxyapatite particles can been achieved simultaneity. Nano-hydroxyapatite particles obtained by in situ precipitation technique were distributed in organic matrices homogeneously and had ideal matching with organic phase, and combination of the two phases was greatly improved, so the synthesized composites have excellent thermodynamic stability. Furthermore, this in situ precipitation can spare the advance synthesis of inorganic phase which can reduce cost of raw materials, and it can achieve some special ultrastructure of the materials. Based on above homogeneous nona-hydroxyapatite/organic hydrogel composite, nanocomposite scaffolds with hierarchical porosity were prepared by means of a multilevel lyophilization, the nanocomposite scaffold mimic structures of bone from microcosmic to sub microcosmic scale which make it more appropriate to bone biomimetic applications at different structural level, and it can be expected to have more bioactivity and mechanical property. At this study, we began with synthesized polymer hydrogel—polyacrylic acid, then gone through natural chitosan hydrogel, at last emphasized on the natural collagen polymer which is the primary organic component in bone tissue. These selected organic matrixes have close affiliation which approach the component of natural bone. This study not only reveals rules of multilevel mediation how organic templates controlled the growth of inorganic minerals, develop a new view to biomimetic materials for bone repair, but present a new illuminations for others inorganic/organic nanocomposites. 2.Calcium carbonate crystals were induced by organic polyacrylamide hydrogel and chitosan hydrogel respectively. The morphological and ultrastructural characteristics of the calcium carbonate were performed by means of SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope), the componential characteristics of the inorganic minerals were performed by means of XRD (X-Ray Diffraction Analyzer)and FTIR(F). The experimental results indicate that organic hydrogel templates have great mediation effect on the growth of calcium carbonate, which 3D scaffolds of hydrogel play a role in the frame of structure, and the electronegative groups in the polymer such as carboxyl, amido etc, acted as nucleation site. Calcium carbonate crystals take on a obvious characteristic of powers self-assemble. As this self-assemble structure regulated by organic hydrogel matrices, a growth mode of calcium carbonate crystal was put forward through a mechanism of limited growth and limited amalgamation, and it can describe the cause of formation of powers self-assemble well. 3.Based on above nono-hydroxyapatite/organic hydrogel composite and calcium carbonate with hierarchical configuration, referred with natural biomaterials, such as pearl, shell, etc which were investigated by our group before. A common characteristic can be found easily, that is fractal structure with hierarchical self-resemble. So, we can find out self-resemble feature among all these biomaterials, then describe them in fractal language, and calculate their fractal dimension according to the software equipped with SEM (Scanning Electron Microscope). After knowing about relations between fractal dimension and configuration of material itself, we can generalize fractal rules of different materials, and improved performance of materials through studies of fractal. Key words: biomineralization, hydroxyapatite, calcium carbonate, organic template, nanocomposite, hierarchical configuration, in situ precipitation, template-driven, fractal, homogeneous.