Mechanics of Deformation of Flexible Fibrous Networks

许多有用的材料是由相互连接的纤维网络组成的。这在生物材料（如组织和细胞）以及人造材料（如纸和纺织品）中都可以观察到。抵抗外力是这些材料的关键特性。尽管如此，目前尚不清楚纤维的机械特征和纤维之间的交联分布如何决定整个网络的刚度。在这里，将创建对网络架构具有精确控制的纤维网络。然后对这些材料进行机械测试。因此，这项研究将揭示究竟哪些微观参数的问题最重要的定义网络刚度。具体的结果将测试最近的预测模型的网络力学，并有助于生物材料的机械性能的基本理解。 一般结局将影响人工纤维材料的使用，并对假体和/或组织植入物的设计产生潜在影响。主要研究者将为科学、技术、数学和工程方面的人力资源开发做出贡献。 研究人员将使用基于序列的DNA自组装合成纤维网络，并使用一系列流变学方法测试其机械性能。 网络将使用双组分策略设计，其中连接器连接到多臂节点。结果，将可能独立地改变连接件的弯曲刚度和拉伸刚度以及节点的连接性。调查将集中在所谓的“边缘凝胶”（即网络的连接是在附近的麦克斯韦均衡点），预计有显着的机械性能与热力学临界行为，包括突然硬化与连接，和临界波动。 学院实习机会和通过跨学科的研究生培训将提供。将通过学生交流和生物分子网络国际夏季研讨会进行国际合作。

Many useful materials are made up of interconnected networks of fibers. This is observed both in biological materials (such as tissues and cells) as well as in man-made materials (such as paper and textiles). Resistance to external forces is a key property of these materials. Still, it is not understood how the mechanical characteristics of the fibers and the distribution of the cross-links between fibers determine the stiffness of the entire network. Here, fibrous networks with precise control over network architecture will be created. These materials will then be tested mechanically. Thereby, this research will reveal exactly which microscopic parameters matter most in defining network stiffness. Specific results will test a recent predictive model of network mechanics and contribute to the fundamental understanding of the mechanical properties of biomaterials. General outcomes will influence the use of artificial fibrous materials, with potential impacts for the design of prosthetics and/or tissue implants. The Principal Investigators will contribute to human resource development in Science, Technology, Math and Engineering. The investigators will synthesize fibrous networks using sequence-based self-assembly of DNA, and test their mechanical properties using an array of methods of rheology. Networks will be designed using a two-component strategy in which linkers are attached to multi-armed nodes. As a result, it will be possible to independently vary the bend stiffness and stretch stiffness of the linkers, as well as the connectivity of the nodes. Investigation will focus on so-called "marginal gels" (i.e. networks whose connectivity is in the vicinity of the Maxwell isostatic point) that are predicted to have dramatic mechanical properties associated with thermodynamic critical behavior, including a sudden stiffening with connectivity, and critical fluctuations. College internship opportunities and through cross-disciplinary graduate student training will be provided. International collaboration via student exchanges and through an international summer workshop on biomolecular networks will be conducted.