HYBRIDIZED DENTIN: BIOMIMETIC MODELING AND OPTIMIZATION

描述（由申请人提供）：牙本质修复界面的强度、耐久性和不渗透性在牙齿修复过程中至关重要，因为修复后该界面的任何破坏都会为毒素和细菌渗透到牙髓中打开通道。近年来，在粘接过程中，粘接剂渗透到脱物质的牙本质中，在该界面处形成杂化牙本质已经受到了相当大的关注。分析和形态学研究表明，混合层是胶原纤维和粘合剂材料的紧密分子混合物。在粘接过程中，允许粘合剂单体渗透到牙本质亚表面上因脱矿作用而打开的空隙中。在渗透到牙本质的亚表面期间，单体与胶原原纤维相互作用，随后聚合以向杂交结构提供强度。光谱研究还不能完全表征界面结构，特别是粘合剂-胶原相互作用。不同的研究者基于相似或不同的实验得出了相互矛盾的结论。研究杂交牙本质的一种创新方法是通过计算机模拟来探测潜在的相互作用。本申请中概述的研究是胶原蛋白和单体结构及其相互作用的计算机辅助仿生建模新方法的延续。申请人在NIH通过AREA赠款支持的可行性研究中开发了这种方法。在这项研究中，优化的构象状态的模型结构的三螺旋胶原蛋白受体和单体分子和由它们的相互作用产生的复合物将被可视化和它们的相互作用在原子水平上分析的溶剂的存在下。将表征配体受体分子的反应位点的空间和静电互补性。胶原蛋白-配体复合物形成的相互作用能将计算为货车范德华力、静电和氢键相互作用的累积效应。将分析这些能量贡献，以确定每种单体的主要相互作用模式。配体和胶原之间的结合研究将通过：1）我们开发的新型免疫化学结合测定法;和2）等温滴定量热法，并与计算的相互作用能值相关。

DESCRIPTION (provided by applicant): The strength, durability and impermeability of the dentin-restoration interface are of critical importance during tooth restoration because any post-restoration breakdown of this interface opens up pathways for toxins and bacteria to penetrate into the pulp. In recent years, there has been considerable focus on the formation of hybridized dentin at this interface by the infiltration of adhesives into the dematerialized dentin during bonding. Analytical and morphological studies have revealed the hybrid layer to be an intimate molecular mixture of collagen fibrils and adhesive material. During bonding adhesive monomers are allowed to permeate into the vacant spaces on the subsurfaces of dentin opened up by demineralization. During infiltration into the sub-surface of dentin, the monomer interacts with collagen fibrils and is subsequently polymerized to provide strength to the hybridized structure. Spectrographic investigations have not been able to fully characterize the interface structure, especially the adhesive-collagen interaction. Different investigators have arrived at conflicting conclusions based on similar or different experiments. One innovative approach to study hybridized dentin is to probe potential interactions through computer simulations. The research outlined in this application is a continuation of a novel method of computer-aided biomimetic modeling of collagen and monomer structures and their interactions. The applicant developed this method in a feasibility study supported by the NIH through an AREA grant. In this study, optimized conformational states of model structures of the triple helical collagen receptor and the monomer molecules and the complex generated by their interaction will be visualized and their interactions in the presence of a solvent analyzed at the atomic level. The steric and electrostatic complementarity of the reactive sites of the ligand receptor molecules will be characterized. The interaction energy for the formation of the collagen-ligand complex will be calculated as the cumulative effect of van der Waals, electrostatic and hydrogen bonding interactions. These energy contributions will be analyzed to determine the predominant mode of interaction for each monomer. Binding studies between the ligands and collagen will be conducted by:1) a novel immunochemical binding assay developed by us; and 2) isothermal titration calorimetry, and related to computed interaction energy values.