Structured Rigid Rod Framework Gels from Clickable Synthetic Polypeptides

技术概述：经典的聚合物网络，特别是水合和溶剂化的交联凝胶，通常是由随机共价交联的聚合物骨架形成的。这类系统的大多数系统研究涉及产生具有有效网格尺寸的结构，这些结构在传统的化学交联系统中是分子性质的，并由随机交联化学定义。该项目涉及构建高度控制的聚合物网络，该网络由刚性棒α -螺旋多肽组成，这些多肽被短官能团或低聚基功能化，这些官能团赋予溶解度、电荷、螯合或配体基团，以及对网络系统的响应行为，具有模块化的控制水平。该系统利用多功能点击化学进行功能化，可以设计随机交联，将螺旋棒状多肽链连接到网络上，或者，棒状多肽链可以通过多臂连接器在端基连接在一起，以提供高度定义的网络结构，其网状结构的大小由聚合物的延伸链长度决定，而机械性能则受主链刚度的影响。与传统的无规线圈聚合物形成的网络不同，螺旋结构的高持久长度和棒状刚性可以提供开放的网状结构。通过将不同的官能团附加到骨架上，应该可以创建独特的凝胶结构，可以在网状结构内部呈现溶剂化，反应性或螯合性基团，并表现出可控的机械性能。这项工作的智力价值涉及到基础化学和物理的实现，以探索这些新型凝胶/网络结构的控制，自由地修改侧基以操纵其他凝胶性质，以及操纵结构和结构以获得凝胶系统的功能隔离和关键结构方面，如网格大小和水水合作用。该项目的具体目标是：1)开发和扩展可点击合成多肽的合成方法；2)研究新型多肽构象控制结构框架水凝胶；3)研究响应网框架凝胶系统，其完全响应行为是由于刚性框架内低聚侧链构象的变化；4)展示了独特功能的结合，以实现离子选择膜或电解质等应用的新特性，以及具有独特解耦机械、运输和配体特性的生物材料的三维基质。非技术总结：新型聚合物网络将使用化学合成方法生成聚合物水凝胶，其中使用模仿某些天然生物分子行为的相对刚性段来加强凝胶，同时保持开放的网状结构以供分子运输。凝胶将被一系列反应性化学基团功能化，实现独特的性能，如离子的选择性运输，特定分子的隔离，反应性，温度或pH响应门控行为。通过在分子刚性棒凝胶体系中探索这一新概念，为开发用于组织再生、药物释放系统、水分离膜和用于太阳能、电池和其他电化学能源和存储应用的固态电解质的新型仿生水凝胶提供了机会。对高中学生的指导和推广以及未来的教师发展活动也将是拟议计划的关键部分，包括参与PI参与高中生和本科生的推广计划。PI也是美国国家科学基金会资助的开放化学多样性公平合作（氧化物）和国家多样性公平研讨会（NDEW）的共同研究者，该研讨会旨在解决化学科学院系的多样性代表性问题，以及材料化学的未来教师研讨会。

TECHNICAL SUMMARY:Classical polymer networks, in particular hydrated and solvated crosslinked gels, are typically derived from random covalently crosslinked polymer backbones. Most systematic studies of such systems involve the generation of structures with an effective mesh size that is molecular in nature in a traditional chemically crosslinked system, and defined by random crosslink chemistry. This project involves the construction of highly controlled polymeric networks consisting of rigid rod alpha-helical polypeptides functionalized with short functional groups or oligomeric groups that impart solubility, charge, chelating or ligand groups, and responsive behavior to the network system with modular levels of control. The systems, which utilize a versatile click chemistry for functionalization, can be designed with random crosslinks that link the helical rod-like polypeptide chains to the network, or alternatively, the rods can be linked together at their endgroups through multi-arm linkers to provide highly defined network structures whose mesh size is determined by the extended chain length of the polymer, and mechanical properties influenced by the rigidity of the backbone. Unlike the networks formed from traditional random coil polymers, the high persistence length and rod-like rigidity of the helical structure can provide an open mesh structure. By appending different functional groups to the backbone, it should be possible to create unique gel structures that can present solvated, reactive or chelating groups within the interior of the mesh structures and exhibit controlled mechanical properties. The intellectual merit of this work involves the implementation of fundamental chemistry and physics to explore the control of these novel gel/network architectures with the freedom to modify side groups to manipulate other gel properties, and manipulation of architecture and structure to gain isolation of function and key architectural aspects of the gel system such as mesh size and water hydration. The specific aims of this project are to: 1) develop and extend the synthetic approaches to clickable synthetic polypeptides; 2) investigate new polypeptide conformationally controlled structured framework hydrogels; 3) investigate responsive mesh framework gel systems for which the full responsive behavior is due to the changes in conformation of oligomeric side chains within the rigid framework and 4) demonstrate the incorporation of unique functionality to achieve novel properties for applications such as ion selective membranes or electrolytes and three dimensional matrices for biomaterials with unique decoupled mechanical, transport, and ligand properties.NON-TECHNICAL SUMMARY:New types of polymeric networks will be generated using chemical synthetic methods to create polymer hydrogels in which relatively rigid segments that mimic the behavior of some natural biomolecules are used to strengthen gels while maintaining open mesh structures for molecular transport. The gels will be functionalized with a range of responsive chemical groups, enabling unique properties such as selective transport of ions, sequestration of specific molecules, reactivity, and temperature or pH responsive gating behavior. By exploring this new concept in the generation of molecular rigid rod gel systems, opportunities exist for development of new biomimetic hydrogels for tissue regeneration, drug releasing systems, water separation membranes, and solid state electrolytes for solar, battery and other electrochemical energy and storage applications. Mentoring and outreach to high school age students as well as future faculty development activities will also be a key part of the proposed program, including participation of the PI in outreach programs that engage high school students and undergraduate students. The PI is also a co-Investigator in the NSF funded Open Chemistry Collaborative in Diversity Equity (OXIDE) and National Diversity Equity Workshop (NDEW) for addressing diversity representation in the chemical science faculties, as well as the Future Faculty Workshop for Materials Chemistry.