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

该奖项将研究颗粒如何在复杂的柔顺微尺度系统中流动，其中颗粒或限制环境的变形会影响颗粒的传输。许多生物和工程结构在微尺度上，如细胞膜、生物膜和微流体装置，是柔软的，因此容易被流体流动变形。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。由于与携带流体的相互作用，这些变形改变了悬浮实体（例如细胞或微生物）的运动。该项目将量化这些相互作用机制，这对于理解微尺度的生物运输非常重要，并建立使用柔顺结构来操纵生物医学应用中的颗粒或细胞悬浮液的仿生系统。此外，该奖项将通过吸引或让本科生和研究生以及初中和高中教师参与其研究来促进教育和推广活动。作为加州大学河滨分校和特拉维夫大学之间的一项合作，它还将有助于加强包括妇女在内的代表性不足群体在河滨县和特拉维夫（以色列）的参与。该奖项将研究由柔性弹性膜限制的颗粒悬浮液的动力学，这在微观尺度的生物环境中无处不在。研究人员将利用解析理论、数值模拟和实验相结合的方法，对微尺度系统中悬浮运输的水弹性机制有一个基本的了解。在项目过程中，国际团队将开发(i)膜附近粒子之间水弹性相互作用的新颖理论和降阶模型，（ii）一个新的非线性水弹性迁移框架，辅以膜附近多粒子动力学的数值模拟，以及（iii）在宏观和微观环境下可视化、表征和量化粒子-膜相互作用的新实验研究。最后，从这些研究中获得的基本见解将用于开发一种微流体装置，以根据其机械和几何特性对囊泡和软颗粒进行操作和分类。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。

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.