CAREER: Symmetry-based microfluidics and perturbation-free micromanipulations of swimming microorganisms

精确控制小几何形状的流体流动，或微流体，已被用作控制或输送小颗粒的有力手段。微流体可以潜在地用于操纵微生物，以研究它们如何感知其环境的机械特性（机械感觉）。充分了解这些微生物的机械感觉可能会导致机械控制它们的行为，作为传统化学处理在生态、环境和健康应用中的替代方案。微加工技术的进步使得微流控器件的几何形状越来越复杂，这些器件内部的流动可以用计算流体动力学来预测。该项目探索了与微生物微操作相关的微流体流动的基本原理，使用了一种称为基于对称的抽象技术。为该项目开发的先进微流体和三维成像技术可以直接转移到许多生物，医学和工业应用中。提议的努力还包括值得注意的教育组成部分，包括“虚拟成像实验室”和“基里伽米-折纸微流体”外展计划，将互动研究体验带到常规教室和虚拟公众。该项目的目标是建立一个基于对称的理解框架，然后为高级微操作调制微尺度流动模式。这种水平的可控微流体环境将用于隔离微生物对周围介质的被动机械反应和主动反应。这种功能将提高我们对机械效应的理解，并导致生物控制的机械处理。该方法是：(i)开发和实验测量基于对称性的微流体基础，用于高级操作功能，（ii）将这些功能扩展到对活细胞的无扰动操作（通过建立“细菌跑步机”），以及（iii）最终实现无通道和像素化微流体应用。通过桥接流动模式和流动的对称性，一个更广泛的设计空间的微流体超越简单的几何是可用于先进的微流体应用。通过流动对称稳健地从机械扰动中分离微生物，在无扰动和机械扰动条件下对微生物进行可控比较变得可行。这种比较将定量地提供微生物对周围介质的机械反应。这种认识也为我们提供了一种严谨的方法来探索游泳微生物的真正水动力效应。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Precise control of fluid flow in small geometries, or microfluidics, has been used as a powerful means of controlling or transporting small particles. Microfluidics can be potentially used to manipulate microorganisms to study how they sense the mechanical properties of their environment (mechanosensation). Gaining a full understanding of the mechanosensation of these microorganisms may lead to mechanical control of their behavior as an alternative to the traditional chemical treatments in ecological, environmental, and health applications. The advancement in microfabrication techniques has yielded increasingly sophisticated geometries in microfluidic devices, and the flow within these devices can be predicted using computational fluid dynamics. This project explores the fundamental principles that govern microfluidic flows relevant to micromanipulation of microorganisms, using a technique called symmetry-based abstraction. Advanced microfluidics and three-dimensional imaging techniques developed for this project can be directly transferable to many biological, medical, and industrial applications. The proposed endeavor also consists of notable educational components, including “Virtual Imaging Lab” and “Kirigami-Origami Microfluidics” outreach programs that bring interactive research experiences to both the regular classroom and virtually to the public.The goal of this project is to establish a symmetry-based framework of understanding and then modulating microscale flow patterns for advanced micromanipulations. This level of controlled microfluidic environment will be used for isolating the passive mechanical responses of microorganisms to surrounding media from active responses. This functionality will elevate our understanding of the mechanical effects and lead to mechanical treatments for biological controls. The approach is to (i) develop and experimentally measure a symmetry-based foundation of microfluidics for advanced manipulation functions, (ii) extend these capabilities to perturbation-free manipulations of living cells (by building a “bacterial treadmill”), and (iii) ultimately realize channel-free and pixelated microfluidic applications. By bridging flow patterns and flow symmetries, a broader design space of microfluidics beyond simple geometries is made available for advanced microfluidic applications. By robustly isolating the microorganisms from mechanical perturbations through flow symmetries, a controlled comparison of microorganisms under perturbation-free and mechanically perturbed conditions becomes viable. This comparison will quantitatively provide the mechanoresponses of microorganisms to surrounding media. This understanding also provides us a rigorous approach to explore the true hydrodynamic effects of swimming microorganisms.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.