Biomimetic Synthesis of an Enamel-Like Material

描述（由申请人提供）：生物技术的最新进展使得牙釉质细胞外基质的蛋白质和蛋白酶可用，并促进了它们在体外功能的研究，以及允许首次尝试在人工环境中合成这种钙化组织。当前提案的总体目标是确定所需的物理化学条件，以蛋白质为导向开发一种与人类牙釉质的组成、结构和特性相媲美的材料。这项工作将有助于我们更好地了解淀粉原蛋白、剪接变体LRAP+和两种蛋白酶在离子和分子水平上如何在生物矿化过程中发挥作用，以及如何利用这些信息在体外合成牙釉质。要测试的假设是，在特定的物理化学条件下，当与选定的蛋白酶结合在矿化溶液中，使用全长和剪接的人类淀粉原蛋白，包括成分、微观结构和性能在内的类搪瓷材料薄层的仿生合成是可行的。这一假设将通过以下三个具体目标进行验证：(1)确定促进全长淀粉原蛋白和剪接变体LRAP+介导的生物矿化的物理化学条件；(2)确定淀粉原诱导的生物矿化是否取决于磷灰石基质的晶体取向；(3)矿化过程中，利用重组MMP-20和丝氨酸蛋白酶逐渐降解淀粉原基质，合成类搪瓷材料。

DESCRIPTION (provided by applicant): Recent advances in biotechnology made proteins and proteases of the extra cellular matrix of enamel available and facilitate the study of their function in-vitro as well as allowing the first attempts to synthesize this calcified tissue in an artificial environment. The overall objective of the current proposal is to determine the physical-chemical conditions required for a protein-guided development of a material that is comparable to the composition, structure and properties of human enamel. This work should lead to an improved understanding of how amelogenin proteins, the spliced variant LRAP+ and two proteases function in the biomineralization process on an ionic and molecular level and how this information can be used to synthesize enamel in-vitro. The hypothesis to be tested is that a biomimetic synthesis of thin layers of an enamel-like material, including composition, microstructure and properties is feasible by the use of full-length and spliced human amelogenins, when combined with selected proteases in mineralizing solutions at specific physical-chemical conditions. This hypothesis will be tested by the following three specific aims: (1) To determine the physical-chemical conditions that promote biomineralization mediated by full-length amelogenin and the spliced variant LRAP+; (2) To determine if amelogenin-induced biomineralization depends on the crystallographic orientation of the apatite substrate; and (3) To synthesize an enamel-like material by gradually degrading the amelogenin matrix using recombinant MMP-20 and serine proteinase while mineralization proceeds.