HYBRIDIZED DENTIN: BIOMIMETIC MODELING AND OPTIMIZATION

描述(申请人提供)：牙本质修复界面的强度、耐用性和防渗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打开毒素和细菌渗透到牙髓的通道。近年来，通过粘接过程中粘结剂渗入脱质牙本质，在牙本质界面形成杂交牙本质的研究受到了广泛关注。分析和形态研究表明，杂化层是胶原纤维和粘合剂材料的亲密分子混合物。在粘接过程中，粘接单体被允许渗透到牙本质底面上因脱矿而打开的空隙中。在渗透到牙本质亚表面的过程中，单体与胶原纤维相互作用，随后被聚合，以提供杂交结构的强度。光谱学研究还不能完全表征界面结构，特别是胶粘剂与胶原的相互作用。不同的研究人员根据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索潜在的相互作用。本申请中概述的研究是对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的新方法的继续。申请者在一项可行性研究中开发了这种方法，该研究由美国国立卫生研究院通过一项区域拨款提供支持。在本研究中，将可视化三螺旋胶原受体和单体分子的模型结构的优化构象状态以及它们相互作用产生的络合物，并在原子水平上分析它们在溶剂存在下的相互作用。配基受体分子反应部位的空间互补和静电互补将被表征。形成胶原-配体复合体的相互作用能将计算为范德华、静电和氢键相互作用的累积效应。将对这些能量贡献进行分析，以确定每个单体的主要相互作用模式。配体与胶原之间的结合研究将通过以下方式进行：1)我们开发的一种新的免疫化学结合试验；2)等温滴定热法，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.