Biomineralization Processes on Natural and Synthetic Substrates

生物矿化的材料，如软体动物的外壳是复杂的 无机单晶和生物聚合物的层状聚集体 其在低温下形成，具有优异强度， 结晶有序 生物合成过程给出， 无机物和蛋白质结构有着令人难以置信的规律， 纳米级（原子）尺寸，和2）初始和 中尺度生长终止（大于 大约0.1微米）的尺寸，从而产生高度的 有序的微层压复合材料的形成， 从而使生物材料具有强度和柔韧性。 这 跨学科研究将探讨基本的 化学和立体化学的相互作用， 水平控制这种生物介导的矿物成核， 在纳米和介观结构水平上的生长。 成核和 无机相的生长将从溶液中进行， 低温和低压：i）无机和生物 无机模板; ii）具有光学性质的合成有机模板 活性基团和类似于那些的离子位点的表面阵列 在体内生物聚合物模板表面上发现;和iii） 生物模板多肽。 拟议的实验将 使用合成和表征的新颖组合， 技术，包括多肽测序和合成， 形成结构导向模板，原位原子力 显微镜和掠入射X射线衍射。 %%% 自然界对模板的使用涉及材料生长， 在低温和低压下的溶液， 目前只有很少的了解和使用的材料 科学家 越来越明显的是，这些新 被称为"化学键合"的材料 陶瓷"具有卓越的抗弯强度。 拟议 这项研究的活动预计将导致发展 低温机械合成的新方法 使用纳米结构的上级和/或高度取向的材料 设计和合成技术。 希望随着更多的光线 涉及的模板机制，模板动力学 将得到改善，模板导向材料合成可以 在更短的时间内完成。 虽然这项研究最初将集中在 软体动物的矿化过程，其中特别涉及 CaCO3的生长，所有的多细胞生物似乎已经进化 用化学上类似的工具来进行基因控制 矿物的成核和生长。 因此，我们希望， 实验将增加对相关领域的洞察力， 生物矿化，包括骨生长。 通过更充分地 认识到矿化是如何在一个特定的 物种，更复杂的生物矿化问题的答案 必定会追随。 我们的研究结果对医学的影响 场是可预见的;骨成核生长是基于 相同的基本化学和结构相互作用 在软体动物壳中，除了成核大分子是 包围矿化的一部分类脂膜 空间 因此，羟基磷灰石成核到这种 脂双层表面可以跟随。 另一方面， 对可溶性生长抑制剂的了解可能有助于 防止不希望的晶体生长。 医学实例 包括牙菌斑，器官结石，动脉硬化， 以及植入心脏瓣膜的钙化。 工业 冷却系统、石油回收系统和市政用水 供应，不希望的水形成的CaCO3水垢沉积物， CaSO4污处理设施。 新的有机化合物可能 抑制结垢形成，是成本有效的，并且在 更大的温度、pH值和盐度范围。

Biomineralized materials such as molluscan shells are complex lamellar aggregates of inorganic single crystals and biopolymers that form at low temperature with exceptional strength and crystalline ordering. The biosynthesis process gives and incredible regularity to 1) inorganic and protein structure at nanoscale (atomic) dimensions, and 2) the initiation and termination of growth at mesoscale (is greater than approximately 0.1 microns) dimensions, thus generating the highly ordered microlaminate composite formation that gives the resulting biomaterial its strength and flexibility. This interdisciplinary research will investigate the fundamental chemical and stereochemical interactions which, at the molecular level control such biologically mediated mineral nucleation and growth at both the nano- and mesostructure level. Nucleation and growth of inorganic phases will be carried out from solutions at low temperatures and pressures on: i) inorganic and biological mineral templates; ii) synthetic organic templates with optically active groups and surface arrays of ionic sites similar to those found on biopolymeric templating surfaces in vivo; and iii) biogenic templating polypeptides. The proposed experiments will use a novel combination of synthesis and characterization techniques, including polypeptide sequencing and synthesis to form structure directing templates, in situ atomic force microscopy and grazing incidence X-ray diffraction. %%% Nature's use of templating involves material growth from solutions at low temperatures and pressures, a process that is currently only poorly understood and little used by materials scientists. Increasingly, it is becoming apparent that these new materials, which have been referred to as "chemically bonded ceramics", have exceptional flexural strength. The proposed activity of this research is expected to lead to the development of new methods for the low temperature synthesis of mechanically superior and/or highly oriented materials using nanostructure design and synthesis techniques. It is hoped that as more light is shed on templating mechanisms involved, templating kinetics will be improved and template-directed materials synthesis can be done on a faster time scale. While the research will initially be centered around the mineralization processes of molluscs, which specifically involves CaCO3 growth, all multicellular organisms appear to have evolved with chemically similar tools for carrying out genetic control over mineral nucleation and growth. We therefore expect that our experimentation will increase insight on related areas of biomineralization, including bone growth. By more fully realizing how mineralization is orchestrated in one particular species, the answers to more complex biomineralization problems will surely follow. Implications of our results for the medical field are foreseeable; bone nucleation growth is based on the same fundamental chemical and structural interactions as occurs in mollusc shells, except that the nucleating macromolecules are part of a bilipid membrane which encloses the mineralization space. Thus, the study of hydroxyapatite nucleation onto such lipid bilayer surfaces may follow. On the other hand, a greater understanding of soluble growth inhibitors can be useful for the prevention of undesirable crystal growth. Medical examples include dental plaque, organ stones, hardening of the arteries, and calcification of implanted heart valves. In industrial cooling systems, oil recovery systems, and municipal water supplies, undesirable water-formed scale deposits of CaCO3 and CaSO4 foul treatment facilities. New organic compounds may inhibit scale formation, be cost effective, and be useful over a larger range of temperatures, pH, and salinity.