Self-healing metallopolymers: From the biological model to synthetic materials

该项目的目的是开发基于贻贝基底线作为生物原型的生物启发自修复金属聚合物。无数的生物材料具有适应性自愈反应，增加了材料寿命，促进了生物体的生存。在化学水平上，通过更高的长度尺度，对这种自然角色模型的潜在设计范式有更深入的了解，这对激发自修复聚合物的发展具有强大的潜力。例如，贻贝丝是一种基于蛋白质的生物含金属大分子，近年来由于其内在的和自主的自我修复能力而受到广泛关注。模仿这种非凡材料的早期努力显示出了希望；然而，实现完全功能的自修复聚合物需要在化学（分子）水平上对结构-功能特性有更深入的了解。最近的证据表明，大丝线的愈合依赖于具有可逆断裂组氨酸-金属交联的分层结构的聚合物（蛋白质）构建块。该项目将生物化学和聚合物化学结合在一起，以确定治疗所需的结构和化学设计标准，目标是将这些原则整合到合成聚合物系统中。提出的生物模型系统的工作包括对金属结合肽结构域的体外化学，结构和力学研究，这些结构域先前与粗丝的愈合行为有关。此外，还将对提取的大纤维蛋白的组装行为进行研究，这将为聚合物的加工提供理想的灵感。这些研究将提供关于结构和层次顺序以及结合基序的重要信息和具体参数，这些信息和参数将直接应用于合成聚合物的设计（基于具有组氨酸的层次结构聚合物）。由此产生的生物启发材料将采用应用于其生物对应物的相同方法进行详细研究，以评估生物学概念转移的程度。这种方法将能够在相同的测量条件下直接比较天然和合成材料，这将进一步允许对生物结构-功能假设进行独立验证。重要的是，合成系统更容易适应生物系统中不可能发生的变化和改变，这将允许进一步探索结构-性质关系。该项目的成功完成需要合作双方的密切互动，并涉及思想、能力和表征技术的协同交流，最终将在具有内在愈合行为的分层结构聚合物材料中达到高潮。

The aim of the project is to develop bio-inspired self-healing metallopolymers based on mussel byssal threads as a biological archetype. Countless biological materials possess an adaptive self-healing response that increases the material lifetime and promotes survival of the organism. A deeper understanding of the underlying design paradigms of such natural role models at the chemical level up through higher length scales has a strong potential to inspire the development of self-healing polymers. Mussel byssus threads, for example, are protein-based biological metal-containing macromolecules that have gained much attention in recent years due to their intrinsic and autonomic self-healing abilities in the absence of living cells. Early efforts to mimic this remarkable material have shown promise; however, realizing fully functional self-healing polymers requires a deeper understanding of the structure-function properties on a chemical (molecular) level. Recent evidence demonstrates that healing in byssal threads depends on hierarchically-structured, polymer (protein) building blocks that possess reversibly breakable histidine-metal cross-links. This project brings together biochemistry and polymer chemistry to determine the structural and chemical design criteria essential to healing with the goal of integrating these principles into a synthetic polymer system. The proposed work on the biological model system consists of an in vitro chemical, structural and mechanical investigation of metal-binding peptide domains that have been previously implicated in the healing behavior of byssal threads. Additionally, studies on the assembly behavior of extracted byssal proteins will be performed, which will ideally provide inspiration for polymer processing. These studies will provide vital information and specific parameters on the structural and hierarchical order and the binding motifs that will be directly applied and utilized for the design of synthetic polymers (based on hierarchically-structured polymers with histidine). The resulting bio-inspired materials will be investigated in detail with the same methods applied for their biological counterparts in order to assess the degree to which biological concepts have been transferred. This approach will enable the direct comparison of the natural and synthetic materials under the same measurement conditions, which will furthermore allow an independent verification of biological structure-function hypotheses. Importantly, the synthetic system is more amenable to variations and alterations not possible in the biological system, which will permit the further exploration of structure-property relationships. Successful completion of the proposed project requires the close interaction of both partners and involves a synergistic exchange of ideas, competencies and characterization techniques, which will ultimately culminate in a hierarchically structured polymeric material possessing intrinsic healing behaviors.