Materials World Network: Microscopic Models of Cross-Linked Active Gels

该奖项支持美国锡拉丘兹大学、英国布里斯托尔大学和南非斯泰伦博施大学在研究和教育方面的国际合作。这项合作是为了进行理论研究，这将极大地提高我们在体外和体内条件下对细胞骨架细丝和相关马达蛋白网络结构和机械性能的理解。一个重要的结果将是确定物理和生化机制在控制许多细胞功能方面的相对重要性，如运动、力量产生和分裂。拟议研究的成功在很大程度上依赖于合作研究小组在流体力学和非平衡物理(美国)、半柔性聚合物物理(英国)和聚合物凝胶理论(南非)方面的互补专业知识。这项研究的第一部分建立在美国和英国团队对细胞骨架细丝和马达蛋白(活性液体)的纯化(体外)细胞提取物的工作基础上。通过与美国、英国和德国的实验人员密切合作，研究人员将专注于了解细丝灵活性和运动元素的微观属性(例如，电机硬度、动力学属性和加工性)如何影响活动流体的宏观行为。该提案的第二个也是主要部分考虑了活性固体的新领域：细胞骨架(体内)和由活性(马达蛋白)和被动交联剂连接的细胞骨架细丝的体外凝胶。这项拟议的研究将导致对活性凝胶迷人的线性粘弹性行为的理解。在本授奖期间计划的定期学生互访将为三个群体之间的密切合作提供机制，并提供特殊的教育机会和国际研究经验。科学目标的实现将与一些更普遍的好处密切相关。首先，这项研究将在与物理、生物学以及生物和仿生材料相关的领域取得重大科学进展。更好地了解控制细胞内部骨架细胞骨架复杂机械性能的过程，可以为设计新一代纳米级智能材料带来重要进展。这项合作还将通过访问位于开普敦附近的非洲数学科学研究所(AIMS)，为与整个非洲大陆数学科学方面的有天赋的学生建立联系打开大门。最后，合作小组之间的学生和博士后研究人员交流将使所有团队成员，包括本科生，在国际环境下进行研究。在这些交流中建立的关系将作为继续合作的基础，同时促进长期的国际网络。该奖项由数学和物理科学局的材料研究部和国际科学和工程办公室联合资助。

This award supports an international collaboration for research and education among Syracuse University in the USA, Bristol University in the United Kingdom, and the University of Stellenbosch in South Africa. This collaboration is for theoretical studies that will dramatically improve our understanding of the structure and mechanical properties of networks of cytoskeletal filaments and associated motor proteins, under both in vitro and in vivo conditions. An important outcome will be the identification of the relative importance of physical and biochemical mechanisms in controlling many cell functions, such as motility, force generation and division. The success of the proposed research relies crucially on the complementary expertise of the collaborating research teams in hydrodynamics and nonequilibrium physics (USA), in semiflexible polymer physics (UK) and on theories of polymer gels (South Africa). The first part of the research builds on work by the US and UK groups on purified (in vitro) cell extracts of cytoskeletal filaments and motor proteins (active liquids). By working closely with experimentalists in the US, UK and Germany, the researchers will focus on understanding how filament flexibility and microscopic properties of the motile elements (e.g., motor stiffness, dynamical properties and processivity) affect the macroscopic behavior of the active fluid. The second and major part of the proposal considers the new area of active solids: the cell cytoskeleton (in vivo) and in vitro gels of cytoskeletal filaments linked by both active (motor proteins) and passive crosslinkers. The proposed research will lead to an understanding of the fascinating linear viscoelastic behavior of active gels. Regular student exchange visits planned during this award period will provide mechanisms for close collaboration among the three groups and exceptional educational opportunities and international research experience.The achievement of the scientific goals will be closely linked with a number of more general benefits. First, the research will provide significant scientific progress in areas relevant to physics, biology and biological and biomimetic materials. A better understanding of the processes controlling the complex mechanical properties of the cytoskeleton, the internal framework of a cell, can lead to important advances for the design of a new generation of smart materials at the nanoscale. The collaboration will also open the door, through visits to the African Institute for Mathematical Sciences (AIMS) located near Cape Town, to the establishment of contacts with gifted students in the mathematical sciences from throughout the African continent. Finally, student and postdoctoral researcher exchange among the collaborating groups will expose all team members, including undergraduate students, to research in an international setting. The relationships developed during these exchanges will serve as the foundation for continued collaborations, while promoting long-term International networking.This award is jointly funded by the Division of Materials Research in the Mathematical and Physical Sciences Directorate and the Office of International Science and Engineering.