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.

非技术摘要这一奖项支持主动物质中的理论研究和教育，由自动驱动实体的组装组成，例如鸟类羊群或活细胞，从环境中吸收能量以产生协调的运动。将分子尺度注入能量转变为有组织的运动和在宏观尺度上的功能的能力是生活系统的定义特性。然后，人们可能会认为必须通过复杂的通信途径或生化信号来控制该组织。然而，近年来，研究人员已经设计了许多与栩栩如生的综合类似物，从化学反应驱动的微晶状体到能够自组织行为的纳米机器人，这表明了物理相互作用在控制集体行为中的关键作用。 PI和她的团队研究的核心目标是量化基于最小互动集的物理模型可以在生活和工程系统中捕获复杂的组织，并开发和测试此类模型。这项研究将提供一个新的强大数学框架，用于描述自然界的定量新兴现象，在这种框架中，大型群体表现出与个人的协调行为非常不同。与锡拉丘兹大学和普林斯顿大学的实验家合作，PI将采用主动物质范式来确定驱动Xanthus泥浆细菌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循环控制。 PI和她的学生还将对合成微武器的集体行为进行建模，并检查这种主动粒子驱动惰性颗粒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的工程铺平道路。该项目将对从物理学到生物学再到工程学的多个领域产生变革性的影响，并以多种方式使社会受益。例如，通过区分由物理机制而不是遗传学触发的转化，对Xanthus的工作将有助于减少在常规遗传研究中必须研究的大量可能性。该研究将包括本科生，研究生和博士后研究人员的机会。它的高度跨学科性质将在科学与生物工程之间的界面上提供广泛的培训，开放各种就业机会。技术摘要这一奖项支持有关主动问题的理论研究和教育。该名称是指许多相互作用实体组成的扩展系统，这些系统由以微观尺度注入的能量驱动到平衡中，从而破坏了详细的平衡。示例包括许多生物系统，从鸟类羊群到活细胞，再到工程细胞，从运动蛋白激活的体外生物聚合物网络到合成微晶状体。 PI将采用从基于代理的模型到连续现象学的多管齐下方法，并通过与实验者的合作来告知人们对主动物质的组织原理和机制的理解。解决的问题是围绕三个目标组织的：（1）使用最小模型来制定主动物质的非平衡统计力学，并特别注意通过限制引起的空间不均匀行为；（2）通过检查拓扑缺陷的动力学和新兴行为来识别受限几何形状中主动流的通用特性；（3）应用主动物质范式来阐明驱动粘液菌的复杂生命周期的物理机制。自行粒子模型上的工作结合了计算和理论，以解决有关活动系统非平衡统计机制的基本问题，而没有微观时间逆转对称性。它将特别研究在均衡概念方面有效描述的程度。研究拓扑缺陷在驾驶和维持自我维持的活性流中的作用将为表征体内和体外的流动模式之间的过渡，从而为从细胞质到细菌悬浮液之间的过渡提供强大的框架。通过对Xanthus M. Xanthus的工作，PI将证明活跃物质范式为组织生物学数据和隔离物理机制提供了一种有用的方法，以控制生活系统的复杂发展周期。主动物质领域将各种学科的社区汇集在一起，并影响从生物学到材料设计的领域。提议的关于自构粒子模型和主动组装的工作将指导具有编程功能的新材料的开发。关于微生物发展的研究旨在区分由物理机制而不是遗传学触发的转化，并将有助于减少在遗传研究中必须研究的大量可能性。拟议的工作将为研究生和博士后在物理，工程和生物学界面提供广泛的培训，并促进多样化的STEM劳动力的发展。 PI将通过组织会议和学校为年轻科学家提供专业发展机会，继续与科学界的互动。