Collaborative research: The effects of fluid flow on flagellar mechanics and microbial motility

合作研究：流体流动对鞭毛力学和微生物运动的影响

基本信息

批准号：
1700961
负责人：
Arezoo Ardekani
金额：
$ 25.57万
依托单位：
Purdue University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-15 至 2021-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1700961&HistoricalAwards=false
关键词：
Collaborative research effects fluid flow

项目摘要

Swimming cells including plankton, sperm, and bacteria play a crucial role in the environment, in human health, and in industrial systems. These cells breakdown pollutants and waste products, transport DNA during reproduction, and provide a promising source of renewable biofuel. Swimming is a fundamental strategy of many single cells, which use hair-like flagella to swim toward nutrients and mates, and away from toxins. However, sometimes cells must ?swim upstream?, and overcome ubiquitous currents and ambient flow of the fluid in which they swim. The role of fluid flow on flagellar mechanics and the spontaneous movement of cells is not well understood. This research project is studying how fluid flow modifies flagellar motion through a combination of direct imaging and mathematical modeling. This work has broad implications for the development of medical devices and medical treatments, the improvement of bioreactors and biofuel production efficiency, and understanding ecosystem dynamics in oceans, lakes, and groundwater. Ambient velocity gradients are known to lead to strong accumulations of cells in flow regions characterized by high shear rates, and the nature of the cell accumulation is strongly dependent on cell motility, shape, and flagellation. This research project uses a synergistic approach incorporating microfluidics and high-speed imaging with state-of-the-art numerical simulations to: (1) Determine the hydrodynamic effects of flow on the flagellar beating of single, tethered cells; (2) Determine how externally-imposed flow affects the hydrodynamics and transport of free swimming cells through flagellar deformation; (3) Establish how flagellar mechanics couple to collective, self-generated flows in dense suspensions of active cells. This project is opening a new, rich research direction in single cell hydrodynamics, where the role of fluid flow has been largely neglected, despite its many implications for biology, ecology and medicine. The researchers on this project are establishing unique empirical data sets and numerical models that map the effects of external fluid forces on active force generation inside flagella, and such information will be an asset to microbiologists, ecologists, and biophysicists interested in modeling cell locomotion. The project is also extending existing methods to quantify flow-structure interactions by characterizing the deformation of flexible appendages having internal force generation, i.e. flagella. Graduate and undergraduate students supported by this project are receiving unique interdisciplinary training in fluid dynamics and microbial biophysics. A hands-on high-speed imaging interactive exhibit at the Indiana State Museum is incorporating these research themes, which will reach middle school students who attend the museum.

包括浮游生物、精子和细菌在内的游泳细胞在环境、人类健康和工业系统中发挥着至关重要的作用。这些细胞分解污染物和废物，在繁殖过程中运输DNA，并提供有前途的可再生生物燃料来源。游泳是许多单细胞的基本策略，它们利用毛发状的鞭毛游向营养物质和交配对象，并远离毒素。然而，有时细胞必须“逆流而上”，并克服无处不在的电流和它们所游动的流体的环境流动。流体流动对鞭毛力学和细胞自发运动的作用尚不清楚。该研究项目正在研究流体流动如何通过直接成像和数学建模相结合来改变鞭毛运动。这项工作对于医疗设备和医疗的开发、生物反应器和生物燃料生产效率的改进以及了解海洋、湖泊和地下水的生态系统动态具有广泛的影响。已知环境速度梯度会导致细胞在以高剪切速率为特征的流动区域中强烈积累，并且细胞积累的性质强烈依赖于细胞运动性、形状和鞭毛。该研究项目采用将微流体和高速成像与最先进的数值模拟相结合的协同方法，以：（1）确定流动对单个系留细胞鞭毛跳动的流体动力学影响； (2) 确定外部施加的流动如何通过鞭毛变形影响自由游动细胞的流体动力学和运输； (3) 确定鞭毛力学如何与活性细胞密集悬浮液中集体的、自生的流动相耦合。该项目为单细胞流体动力学开辟了一个新的、丰富的研究方向，其中流体流动的作用在很大程度上被忽视，尽管它对生物学、生态学和医学有许多影响。该项目的研究人员正在建立独特的经验数据集和数值模型，以绘制外部流体力对鞭毛内部主动力产生的影响，这些信息对于对细胞运动建模感兴趣的微生物学家、生态学家和生物物理学家来说将是一笔宝贵的财富。该项目还扩展了现有方法，通过表征具有内力产生的柔性附件（即鞭毛）的变形来量化流-结构相互作用。该项目支持的研究生和本科生正在接受流体动力学和微生物生物物理学方面独特的跨学科培训。印第安纳州立博物馆的一个动手高速成像互动展览正在纳入这些研究主题，该展览将吸引参观博物馆的中学生。