Effects of water on molecular and supramolecular structure and mechanical properties of fibrous protein materials

胶原蛋白、丝素或骨等生物结构材料表现出优异的力学性能，这主要是由于它们的结构和相互作用在多个层次(从分子到宏观长度尺度)上的优化。众所周知，水在稳定BMS的二级和三级结构中起着至关重要的作用，并且对最终的力学性能(强度、韧性、弹性等)有很大的影响。它们的天然和仿生材料。此外，通过单独脱水可以观察到每个分子的超常作用力，例如基于胶原蛋白的大鼠尾腱(每个分子的作用力大约是肌球蛋白的20倍)。这种力量产生背后的机制完全不清楚。因此，该项目的主要目标是在分子和超分子水平上了解水化水平与生物结构和性质之间的关系，并将这些特征与BMS的力产生和总体宏观性能相关联。为了评估不同长度尺度的材料，我们计划在受控的环境条件(温度、湿度和力)下将同步X射线和偏振拉曼散射相结合。为了提供可靠的定量信息，表征方法和外部刺激(机械和热)将在现场同时使用。这样的装置将在项目框架内组装和验证，并在德国和其他地方提供独特的实验能力。为了支持实验结果，并模拟与水诱导的力产生和机械性能有关的分子和超分子行为，还将进行最先进的分子动力学模拟。从天然材料研究中提炼出的概念将被用作优化当前仿生策略的指导方针，以生产机械性能可与其天然类似物相媲美的合成材料。利用重组和重组前驱体，将使用静电纺丝和分子自组装技术生产合成纤维和薄膜。该项目的最终目标是将从BMS结构-功能关系研究中学到的经验教训用于开发新的仿生和生物医学应用的设计和生产策略。

Biological structural materials (BMs), such as collagen, silk, or bone show outstanding mechanical performance mainly due to the optimization of their structure and interactions on many levels of hierarchy (ranging from the molecular up to macroscopic length scales). It is well known that water plays a crucial role in stabilizing secondary and tertiary structure of BMs and has huge effect on the final mechanical properties (strength, toughness, elasticity etc.) of their natural and biomimetic materials. Furthermore, extraordinary forces per molecule were observed by solely dehydrating, for example collagen based rat tail tendon (forces per molecule around 20 times those observed for myosin). The mechanism behind this force generation is completely unclear. The main goal of this project is, therefore, to understand the relationship between the level of hydration and biological structure and properties at the molecular and supramolecular scale and correlate these features to the force generation and generally the macroscopic performance of BMs. In order to assess material at various length scales we plan to combine in situ synchrotron X-ray and polarized Raman scattering in controlled environmental conditions (temperature, humidity and force). To provide reliable quantitative information, characterization methods and external stimuli (mechanical and thermal) will be employed simultaneously in situ. Such a setup will be assembled and validated in the framework of the project and provide a unique experimental capability in Germany and beyond. To support experimental outcomes and to model molecular and supramolecular behavior in relation to water-induced force generation and mechanical performance, state-of-the-art molecular dynamics simulations will also be carried out. Concepts distilled from the study of natural materials will be used as guidelines in optimizing current biomimetic strategies to produce synthetic materials with mechanical performance comparable to their natural analogues. Using reconstituted and recombinant precursors, synthetic fibers and films will be produced using electro-spinning and molecular self-assembly techniques. The ultimate goal of this project is to adapt the lessons learned from investigating structure-function relationships in BMs for the development of new design and production strategies for biomimetic and biomedical applications.