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

该项目的目的是开发以贻贝丝线为生物原型的仿生自修复金属聚合物。无数的生物材料具有自适应的自我修复反应，这种反应可以延长材料的寿命，促进有机体的生存。通过更高长度的尺度在化学水平上更深入地理解这些自然角色模型的潜在设计范例，将极大地激励自我修复聚合物的发展。例如，贻贝丝线是一种基于蛋白质的含有金属的生物大分子，由于其在没有活细胞的情况下具有内在和自主的自我修复能力，近年来受到了极大的关注。早期模仿这种非凡材料的努力已经显示出希望；然而，实现全功能自修复聚合物需要在化学(分子)水平上更深入地了解结构-功能特性。最近的证据表明，肌腱的修复依赖于具有可逆断裂的组氨酸-金属交联物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，以确定治愈所必需的结构和化学设计标准，目标是将这些原理整合到一个合成聚合物系统中。拟议的生物模型系统的工作包括对金属结合多肽结构域的体外化学、结构和力学研究，这些结构域以前被认为与肌腱线条的愈合行为有关。此外，还将研究由SSAL提取的蛋白质的组装行为，这将为聚合物加工提供理想的灵感。这些研究将提供有关结构和层级顺序以及结合基序的重要信息和具体参数，这些基序将直接应用于合成聚合物的设计和利用(基于带有组氨酸的层级结构聚合物)。将对产生的生物启发材料进行详细调查，采用适用于生物材料的相同方法，以评估生物概念转移的程度。这种方法将能够在相同的测量条件下直接比较天然材料和合成材料，这将进一步允许对生物结构功能假说的独立验证。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变化，这将允许进一步探索结构与性质的关系。成功完成拟议的项目需要双方的密切互动，并涉及思想、能力和表征技术的协同交流，最终将产生具有内在愈合行为的层次化结构的聚合物材料。

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.