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Dynamics and Mechanics of Active Matter

活性物质的动力学和力学

基本信息

批准号：
1938187
负责人：
Cristina Marchetti
金额：
$ 11.1万
依托单位：
University of California-Santa Barbara
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-01 至 2020-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1938187&HistoricalAwards=false
关键词：
Dynamics Mechanics Active Matter

项目摘要

NON-TECHNICAL SUMMARYThis award supports theoretical research and education in active matter, consisting of assemblies of self-driven entities, such as bird flocks or living cells, that take energy from the environment to produce coordinated motion. The ability to turn energy injected at the molecular scale into organized motion and function at the macroscopic scale is a defining property of living systems. One may then think that such organization must be controlled by complex communication pathways or biochemical signaling. In recent years researchers have, however, engineered a number of synthetic analogues with life-like properties, from microswimmers powered by chemical reactions to swarms of nanobots capable of self-organized behavior, demonstrating the key role of physical interactions in controlling collective behavior. The central goal of the research by the PI and her team is to quantify the conditions under which physical models based on a minimal set of interactions can capture complex organization in both living and engineered systems, and to develop and test such models. The research will provide a new powerful mathematical framework for describing quantitatively emergent phenomena in nature, where large groups exhibit coordinated behaviors that are very different from those of the individuals. Working with experimentalists at Syracuse University and at Princeton University, the PI will employ the active matter paradigm to identify the physical mechanisms that drive the life cycle of the soil-dwelling bacterium Myxococcus xanthus, which is controlled by a continuous feedback loop between collective and individual behavior. The PI and her students will also model the collective behavior of synthetic microswimmers and examine the conditions required for such active particles to drive the assembly and organization of inert particles. This work will pave the way to the engineering of smart materials capable of active-assembly, reconfiguration, and self-healing.The project will have transformative impact across several fields, from physics to biology to engineering, and benefit society in several ways. For instance, by differentiating transformations that are triggered by physical mechanisms as opposed to genetics, the work on M. xanthus will help cut down the vast number of possibilities that must be investigated in routine genetic studies. The research will include opportunities for undergraduates, graduate students and postdoctoral researchers. Its highly interdisciplinary nature will provide broad training at the interface between science and bioengineering, opening up a variety of employment opportunities.TECHNICAL SUMMARYThis award supports theoretical research and education on active matter. This name refers to extended systems composed of many interacting entities that are driven out of equilibrium by energy injected at the microscopic scale, breaking detailed balance. Examples include many living systems, from bird flocks to living cells, and engineered ones, from in vitro biopolymer networks activated by motor proteins to synthetic microswimmers. The PI will use a multipronged approach ranging from agent-based models to continuum phenomenology, and informed by collaborations with experimenters to advance understanding of the organizational principles and mechanics of active matter. The problems addressed are organized around three objectives: (1) using minimal models to formulate the nonequilibrium statistical mechanics of active matter, with specific attention to spatially inhomogeneous behavior induced by confinement; (2) identifying generic properties of active flows in confined geometry by examining the dynamics and emergent behavior of topological defects; and (3) applying the active matter paradigm to elucidate the physical mechanisms that drive the complex life cycle of Myxococcus xanthus. The work on self-propelled particle models combines computation and theory to address fundamental questions on the nonequilibrium statistical mechanics of active systems with no microscopic time reversal symmetry. It will specifically examine the extent to which effective descriptions in terms of equilibrium concepts may be possible. The study of the role of topological defects in driving and maintaining self-sustained active flows will provide a powerful framework for characterizing transitions between flow patterns in biofluids in vivo and in vitro, from the cytoplasm to bacterial suspensions. Through the work on M. xanthus, the PI will demonstrate that the active matter paradigm provides a useful way for organizing biological data and isolate the physical mechanisms at play in controlling complex developmental cycles of living systems. The field of active matter brings together communities from a broad range of disciplines and impacts areas ranging from biology to materials design. The proposed work on self-propelled particle models and active assembly will guide the development of new materials with programmed functions. The research on microbial development aims at differentiating transformations that are triggered by physical mechanisms as opposed to genetics and will help cut down the vast number of possibilities that must be investigated in genetic studies. The proposed work will provide broad training for graduate students and postdocs at the interface of physics, engineering and biology and promote the development of a diverse STEM workforce. The PI will continue her engagement with the scientific community by organizing conferences and school that will provide professional development opportunities for young scientists.

非技术总结该奖项支持活跃物质的理论研究和教育，包括自驱动实体的组件，如鸟群或活细胞，从环境中获取能量以产生协调运动。将分子尺度上注入的能量转化为宏观尺度上有组织的运动和功能的能力是生命系统的定义属性。人们可能会认为，这种组织必须由复杂的通信途径或生化信号控制。然而，近年来，研究人员已经设计了许多具有类似生命特性的合成类似物，从由化学反应提供动力的微型游泳者到能够自组织行为的纳米机器人群，证明了物理相互作用在控制集体行为中的关键作用。PI和她的团队研究的中心目标是量化基于最小交互集的物理模型可以捕获生命和工程系统中复杂组织的条件，并开发和测试此类模型。这项研究将提供一个新的强大的数学框架，用于定量描述自然界中涌现的现象，其中大型群体表现出与个体非常不同的协调行为。与锡拉丘兹大学和普林斯顿大学的实验学家合作，PI将采用活性物质范式来确定驱动土壤细菌粘球菌（Myxococcus xanthus）生命周期的物理机制，该机制由集体和个人行为之间的连续反馈回路控制。PI和她的学生还将模拟合成微泳者的集体行为，并研究这些活性粒子驱动惰性粒子组装和组织所需的条件。这项工作将为能够主动组装、重新配置和自我修复的智能材料工程铺平道路。该项目将在从物理学到生物学再到工程学的多个领域产生变革性影响，并以多种方式造福社会。例如，通过区分由物理机制而不是遗传机制触发的转化，对M。Xanthus将有助于减少常规遗传研究中必须调查的大量可能性。研究将包括本科生，研究生和博士后研究人员的机会。其高度跨学科的性质将在科学和生物工程之间的接口提供广泛的培训，开辟了各种就业机会。技术总结该奖项支持理论研究和教育的活性物质。这个名字指的是由许多相互作用的实体组成的扩展系统，这些实体被微观尺度上注入的能量驱动出平衡，打破了详细的平衡。例子包括许多生命系统，从鸟群到活细胞，以及工程系统，从由运动蛋白激活的体外生物聚合物网络到合成的微型游泳者。PI将采用多管齐下的方法，从基于代理的模型到连续现象学，并通过与实验者的合作来了解，以促进对活性物质的组织原理和力学的理解。所解决的问题围绕三个目标：（1）使用最小模型来表述活性物质的非平衡统计力学，特别关注由约束引起的空间非均匀行为：（2）通过检查拓扑缺陷的动力学和涌现行为来识别受限几何中活性流的一般性质;（3）应用活性物质范式阐明了驱动黄色粘球菌复杂生活史的物理机制。自推进粒子模型的工作结合了计算和理论，以解决没有微观时间反演对称性的活动系统的非平衡统计力学的基本问题。它将具体地研究在何种程度上有效的描述方面的均衡概念可能是可能的。拓扑缺陷在驱动和维持自我维持的主动流动的作用的研究将提供一个强大的框架，在体内和体外，从细胞质到细菌悬浮液的生物流体中的流动模式之间的特征转换。通过对M. xanthus，PI将证明活性物质范式为组织生物数据提供了一种有用的方法，并隔离了控制生命系统复杂发育周期的物理机制。活性物质领域汇集了来自广泛学科和影响领域的社区，从生物学到材料设计。关于自推进粒子模型和主动组装的拟议工作将指导具有编程功能的新材料的开发。对微生物发育的研究旨在区分由物理机制而不是遗传机制引发的转化，并将有助于减少遗传研究中必须调查的大量可能性。拟议的工作将为研究生和博士后提供物理，工程和生物学接口的广泛培训，并促进多元化STEM劳动力的发展。PI将继续与科学界合作，组织会议和学校，为年轻科学家提供专业发展机会。