Collaborative Research: Multiscale Engineering of Active Stress in Biomaterials

非技术摘要：生物系统表现出非凡的行为，包括治愈、繁殖和自我运动的能力。传统的合成材料没有这样的特性，因为它们是由无生命的分子组成的。相比之下，生物系统由活跃的能量传导分子组成，这些分子不断地相互推拉，产生活跃的压力。这些活跃的压力使生物系统成为活跃物质的例子，并最终导致它们的许多不寻常行为。创造人工活性物质开辟了一条构建具有逼真功能的材料的新途径。然而，实现这种可能性的一个重要障碍是缺乏对活动应力是如何产生的了解：给定特定的基本构件，目前还没有工具来测量或从理论上预测活动应力的大小、类型甚至符号。该项目将通过实验、模拟和理论的协同结合来阐明主动应力产生的基本原理。这项工作将创造测量活动应力的新实验工具，创造活性材料的新合成程序，以及研究活性物质的新的多尺度建模技术。一个综合的推广计划将通过互动演示、高级跨学科培训和强化暑期课程，为K-12教育、本科生和毕业生带来活性物质的兴奋。技术摘要：该研究重点是研究微管和Kinesin-14分子马达的组装。这项工作解决了理解由这种活性材料产生的主动应力的三个基本挑战。首先是结合理论和模拟，开发使用光钳、流体流量测量、微流体和3D打印来测量不同长度尺度上的活动应力的工具。第二，将创建一种新的系统，在该系统中，通过以预定的模式直接将激动素-14固定在微管上来调节主动应力的产生。理论和模拟将被用来指导创建哪些图案，反过来，测量这些设计材料中产生的主动应力将提供对理论和模拟的严格测试。第三，将开发和测试多尺度建模框架。这些因素随后将通过分析计算和模拟相结合的方式相互关联。由此产生的模型将通过不断的实验反馈来制作。综上所述，这项工作将建立新的范式来研究、理解和设计活性材料中的活性应力。这项DMR拨款支持研究，以了解微管和Kinesin-14分子马达的组装，资金来自数学和物理科学总监材料研究部的凝聚态物质物理(CMP)和生物材料(BMAT)计划。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Abstract:Biological systems exhibit remarkable behaviors, including the ability to heal, reproduce, and be self-motile. Conventional synthetic materials do not display such properties because they are composed of inanimate molecules. In contrast, biological systems consist of active, energy transducing molecules which continuously push and pull on each other, producing active stresses. These active stresses make biological systems examples of active matter, and are ultimately are responsible for many of their unusual behaviors. Creating artificial active matter opens up a new route towards constructing materials with lifelike functionalities. However, a significant obstacle to realizing this possibility is an absence of understanding of how active stresses are produced: given specific elemental building blocks, there are not currently tools to either measure or theoretically predict the magnitude, type, or even the sign of the active stresses. The project will elucidate the foundational principles of active stress generation using a synergistic combination of experiments, simulations, and theory. The work will result in the creation of new experimental tools for measuring active stresses, new synthesis procedures for creating active materials, and new multi-scale modeling techniques for studying active matter. An integrated outreach program will bring the excitement of active matter to K-12 education, undergraduates, and graduates by combining interactive demonstrations, advanced interdisciplinary training, and intensive summer courses.Technical Abstract:The research focuses on studying assemblages of microtubules and kinesin-14 molecular motors. The work addresses three fundamental challenges in understanding active stresses generated by such active materials. First is the development of tools to measure active stresses at different length scales using optical tweezers, fluid flow measurements, microfluidics, and 3D printing, in combination with theory and simulations. Second, a novel system will be created in which active stress generation will be modulated by directly affixing kinesin-14 to microtubules in predetermined patterns. Theory and simulations will be used to guide which patterns to create, and conversely, measuring the resulting active stress generation in these designed materials will provide a stringent test of theory and simulations. Third, a multi-scale modeling framework will be developed and tested. These will be subsequently related to each other through a combination of analytical calculations and simulations. The resulting models will be made with continual feedback from experiments. Taken together, this work will establish new paradigms to study, understand, and engineer active stresses in active materials.This DMR grant supports research to understand the assemblages of microtubules and kinesin-14 molecular motors with funding from the Condensed Matter Physics (CMP) and Biomaterials (BMAT) Programs in the Division of Materials Research of the Mathematical and Physical Sciences Directorate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.