Dispersion in Microfluidic Suspensions: Experiments and Numerical Simulations

微球和细胞的分散已经成为许多生物和微流体应用中的关键问题。众所周知，通过微通道的压力驱动流会导致？泰勒分散?对于溶质塞，颗粒或生物细胞悬浮塞的分散特性尚未详细探讨。在时间尺度上观察到，由于微通道壁和多粒子流体动力相互作用，颗粒样品具有许多流线。在上述大多数微流体应用中，为了在一定浓度范围内进行反应或测量，只需使用一组样品溶液来填充入口，就需要对试剂进行单次或多次稀释。通常不清楚如何设计稀释通道或通道以实现塞的最小分散。需要对微通道流动中的颗粒通量和混合有新的认识，以开发浓度锋或与完全密集流动相反的强烈不均匀流动的模型。提出的研究和教育计划启动了一个基本的方法来分析微球和生物细胞的微流体悬浮液流动中的分散。该研究计划将开发一个新的实验平台，用于使用不同种类的固体和软颗粒进行基准悬浮塞输运实验。该项目还将开发一种全新的、完全解决的数值模拟框架，用于探索本质上不均匀且可能在短距离内快速变化的隔离悬架桥塞。这些研究将影响我们对微尺度系统中输运的基本理解，并将导致与微反应器设计和两相流相关的不同领域的技术进步，并应用于高通量筛选和生物分离。该项目将对悬浮液和蜂窝塞在不同长度和时间尺度下的运输有一个重要的了解。这将加速对新系统的探索，以高效地进行快速筛选，以检测和分析微小样品。该项目还将为新的研究生研究助理在发展和应用新的研究技术方面提供宝贵的培训。这项工作是微流体装置技术和科学计算的一个基本类别的悬浮流的接口，并将提供跨学科的经验。将有一个协调的外展计划，包括本科生研究项目，并纳入跨学科课程的新材料，以培养生物学，物理学，工程学和应用数学的本科生的新方法。pi将参与并为布朗大学做出贡献？教师研究经验计划（RET）。

1133106PI: MaxeyDispersion of microspheres and cells has become a critical issue in a number of biological and microfluidic applications. While it is well known that pressure driven flows through a microchannel leads to ?Taylor dispersion? of solute plugs, the dispersion characteristics of particulate or biological cell suspension plugs have not been explored in detail. The dispersion is observed on time scales such that the particles sample many streamlines due to microchannel wall and multiparticle hydrodynamic interactions. In most of the above microfluidic applications, single or multiple dilutions of reagents are required in order to perform reactions or measurements over a range of concentrations using only one set of sample solutions to fill the inlets. It is often unclear how to design the dilution channel or channels for achieving minimum dispersion of the plugs. New insights on particle fluxes and mixing in microchannel flows are needed to develop models for concentration fronts or strongly inhomogeneous flows as opposed to fully populated flows. The proposed research and education program launches a fundamental approach to analyze dispersion in microfluidic suspension flow of microspheres and biological cells. The research program will develop a new experimental platform for performing benchmark suspension plug transport experiments using different kinds of solid and soft particles. The program will also develop a new, fully resolved, numerical simulation framework for exploring isolated suspension plugs that are inherently inhomogeneous and may vary rapidly over short distances. These studies will impact our fundamental understanding of transport in microscale systems, and will lead to technological advances in diverse areas relevant to micro-reactor design and two-phase flows with applications to high throughput screening and bio-separations. The project will develop a crucial understanding of transport of suspension and cellular plugs under different length and time scales. This will accelerate the exploration of new systems for performing rapid screening with high efficiency to detect and analyze minuscule samples. The project will also provide valuable training for new graduate research assistants in developing and applying the new research techniques. The work is at the interface of microfluidic device technology and scientific computing for a fundamental class of suspension flows, and will provide cross-disciplinary experience. There will be a coordinated outreach program involving undergraduate research projects and incorporating new material for interdisciplinary courses to train undergraduates from biology, physics, engineering and applied mathematics in new approaches. The PIs will participate in and contribute to Brown University?s Research Experience for Teachers Program (RET).