NSF-BSF: Dynamics of flowing particles in soft confined systems

该奖项将研究粒子如何在复杂的顺应性微尺度系统中流动，其中粒子或限制环境的变形影响粒子传输。许多微尺度的生物和工程结构，如细胞膜、生物膜和微流体装置，都是柔软的，因此很容易因流体流动而变形。红细胞在狭窄的毛细血管中流动时会变形，游动的微生物和流动的微粒会导致细胞膜弯曲和变形。这些变形修改悬挂实体的运动（例如，细胞或微生物）。该项目将量化这些相互作用机制，这对于理解微尺度生物运输非常重要，并构建仿生系统，该系统使用顺应性结构来操纵用于生物医学应用的颗粒或细胞悬浮液。此外，该奖项将促进教育和推广活动，通过从事，或暴露本科生和研究生，以及初中和高中教师，其研究。作为加州大学、滨江大学和特拉维夫大学之间的合作项目，该项目还将在滨江县和特拉维夫（以色列）促进包括妇女在内的代表性不足的群体的参与，该项目将研究在微尺度生物环境中普遍存在的、由柔性弹性膜限制的微粒悬浮液的动力学。研究人员将开发一个基本的理解悬浮液运输在微尺度系统的水弹性机制，使用分析理论，数值模拟和实验相结合。在该项目的过程中，国际团队将开发（i）膜附近颗粒之间水弹性相互作用的新理论和降阶模型，（ii）一个新的非线性水弹性流动性框架，并辅以数值模拟，膜附近的多颗粒动力学，以及（iii）新的实验研究，以可视化，表征，并量化宏观和微观环境中的颗粒-膜相互作用。最后，从这些研究中获得的基本见解将被用于开发一种微流体设备，以根据囊泡和软颗粒的机械和几何特性对其进行操纵和分选。该奖项反映了NSF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。

This award will investigate how particles flow in complex compliant microscale systems, in which deformation of either the particles or the confining environment affects particle transport. Many biological and engineered structures at the microscale, such as cell membranes, biofilms, and microfluidic devices, are soft and thus easily deformed by fluid flow. Red blood cells deform when flowing in narrow capillaries, and swimming microbes and flowing microparticles can cause cell membranes to bend and deform. These deformations modify the motion of the suspended entities (e.g., cells or microorganisms) as a result of interactions with the carrying fluid. The project will quantify these interaction mechanisms, which are important to understand microscale biological transport, and to build biomimetic systems that use compliant structures to manipulate suspensions of particles or cells for biomedical applications. Furthermore, this award will foster education and outreach activities by engaging, or exposing undergraduate and graduate students, as well as middle and high-school teachers, to its research. As a collaboration between the University of California, Riverside and Tel Aviv University, it will also serve to enhance the participation of under-represented groups, including women, in both Riverside County and Tel Aviv (Israel).This award will investigate the dynamics of particulate suspensions confined by flexible elastic membranes, which are ubiquitous in biological environments at the microscale. The researchers will develop a fundamental understanding of hydroelastic mechanisms of suspension transport in microscale systems, using a combination of analytic theory, numerical simulations, and experiments. Over the course of the project, the international team will develop (i) novel theoretical and reduced-order models of hydroelastic interactions between particles near membranes, (ii) a new nonlinear hydroelastic mobility framework, complemented by numerical simulations, of many-particle dynamics in proximity to membranes, and (iii) new experimental studies to visualize, characterize, and quantify particle-membrane interactions in macroscopic and microscopic settings. Finally, the fundamental insights obtained from these studies will be used to develop a microfluidic device to manipulate and sort vesicles and soft particles based on their mechanical and geometric properties.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.