Collaborative Research: Separation of nanoparticles using gradient surfaces: multiscale simulations and experiments

国家科学基金会-化学运输系统分部颗粒多相过程计划（1415）提案编号：0731032主要研究者：Drazer，德国附属机构： 约翰霍普金斯大学提案标题：合作研究：使用梯度表面分离纳米颗粒：多尺度模拟和实验由于微米和纳米颗粒经历布朗运动，因此将颗粒引导到流体装置中的期望位置同时允许它们保持悬浮在溶液中的能力是具有挑战性的。我们设想了一种技术，利用布朗运动本身，通过控制设备边界表面上的能量景观来空间聚焦粒子。我们利用这种粒子聚焦技术来创建用于连续分级悬浮胶体的分离单元。所设想的装置提供了一种基于物质与在装置的边界壁上产生的亲和力梯度的差异相互作用来分离悬浮颗粒的新方法。总体结果是混合物的矢量分离，其中不同的物质在不同的方向上移动，从而允许连续操作，与一维系统相比具有更高的分离能力和峰值容量。该战略是结合联合收割机国家的最先进的微制造，多尺度建模和仿真，设计和实验测试这些微和纳米流体分离devies.Intellectual优点：深入了解颗粒表面相互作用是至关重要的成功设计和优化的建议分离装置。与开发和改进制造纳米级材料或器件所需的实验技术的显著活动和进展相反，用于理解纳米尺度下的传输现象的框架欠发达，特别是在具有显著几何限制的情况下，如在这里感兴趣的情况下，其中通道尺寸与悬浮颗粒的尺寸相当。因此，我们提出了一个合作的努力，结合关键实验与多尺度建模和模拟，所有的目的是了解在流动条件下与几何约束的颗粒表面相互作用的主要方面。科学方面：颗粒的布朗漂移阻碍了想要在流体装置内的特定位置处寻址特定颗粒的应用。在这项工作中研究的聚焦方案可以用来克服这些复杂性，并可以在芯片实验室设备中广泛利用。在这种情况下，这项工作的潜在扩展是广泛的，因为在流体设备中的颗粒操纵领域以及表面特性的主动控制领域具有很高的活性。教育和外联方面：在我们的项目中，粒子表面相互作用产生的基本问题，以及利用分子现象对技术应用的潜在影响，将被纳入为本科生和研究生课程设计的“分子模拟”和“纳米材料中的界面现象”模块中，这些模块目前是参与机构IGERT计划的一部分。这些模块将为学生提供一个明确的例子，说明需要多学科团队，以了解纳米科学中的复杂问题，并能够解决纳米技术中具有挑战性的问题。此外，本项目将提供实践经验，本科生和高中生从不同的推广和教育方案在这两个机构提供绘制。学生将成为多元化研究团队的一部分，因此，将为生物分子和化学工程日益跨学科的领域做好更好的准备。学生将在会议和研讨会上展示他们的成果，并负责维护一个研究网页，及时向公众展示成果。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)Proposal Number: 0731032 Principal Investigators: Drazer, German Affiliation: Johns Hopkins University Proposal Title: Collaborative Research: Separation of nanoparticles using gradientsurfaces: multiscale simulations and experiments The ability to guide particles to a desired location in a fluidic device while allowing them to remain suspended in solution is challenging since micro- and nano-particles undergo Brownian motion. We have conceived a technique that exploits Brownian motion itself to focus particles spatially by controlling the energy landscape on the bounding surfaces of a device. We exploit this particle focusing technique to create separation units for the continuous fractionation of suspended colloids. The conceived devices provide a novel approach to the separation of suspended particles based on the differential interaction of the species with affinity gradients created on the bounding walls of the device. The overall result is the vector separation of the mixture, in which different species move in different directions, thus allowing for continuous operation with higher separation power and peak capacity compared to one-dimensional systems. The strategy is to combine state-of-the-art microfabrication, with multiscale modeling and simulation, to design and experimentally test these micro- and nanofluidic separation devices.Intellectual merit: A deep understanding of particle-surface interactions is crucial to a successful design and optimization of the proposed separation devices. In contrast to the significant activity and advances in developing and refining experimental techniques needed to fabricate nanoscale materials or devices, the framework for understanding transport phenomena at nanometer scales is less developed, particularly in cases with significant geometric confinement as in the case of interest here, in which the channel dimension is comparable to the size of the suspended particles. Therefore, we propose a collaborative effort, combining critical experiments with multiscale modeling and simulations, all aimed at understanding the dominant aspects of particle-surface interactions under flow conditions with geometric confinement.Broader Impact. Scientific aspects: Brownian excursions of particles hamper applications in which one wants to address specific particles at specific positions within a fluidic device. The focusing scheme investigated in this work could be used to overcome those complications, and could be widely exploited in lab-on-a-chip devices. In this context, the potential extensions of this work are broad, given the high activity in the field of particle manipulation in fluidic devices, and in the field of active control of surface properties.Broader Impact. Education and Outreach aspects: The fundamental issues resulting from particle-surface interactions in our project, as well as the potential impact of harnessing molecular phenomena for technological applications, will be incorporated in modules designed for undergraduate and graduate level courses in "Molecular simulations" and "Interfacial Phenomena in Nanomaterials", which are currently part of IGERT programs in the participating institutions. These modules will provide the students with a clear example of the need for multidisciplinary teams in order to understand complex problems in nanoscale science and to be able to address challenging issues in nanotechnology. In addition, the present project will provide hands-on experience to undergraduate and high school students drawn from the different outreach and educational programs available at both institutions. The students will be part of a diverse team of researchers and, as a result, will be better prepared for the increasingly interdisciplinary field of biomolecular and chemical engineering. The students will present their results in conferences and workshops and will be responsible for maintaining a research webpage that will present the results in a timely manner and for the general public.