Collaborative Proposal: Separation of Nanoparticles Using Patterned Surfaces: Multiscale Transport and Experiment

国家科学基金会-化学和运输系统颗粒和多相过程计划部门(1415)提案编号：0731109主要研究人员：Koplik，JoelAffiliation：CUNY City CollegeProposal标题：协作研究：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，将颗粒引导到流体设备中的所需位置，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使粒子在空间上聚焦的技术。我们利用这种颗粒聚焦技术来创建用于悬浮胶体连续分馏的分离单元。构思的装置提供了一种新的方法来分离悬浮颗粒，该方法基于物种与在装置的包围壁上产生的亲和力梯度的不同相互作用。总的结果是混合物的矢量分离，其中不同的物种向不同的方向移动，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容量。该战略是将最先进的微制造与多尺度建模和模拟相结合，以设计和实验测试这些微/纳米流体分离设备。智力优势：对颗粒-表面相互作用的深入理解对于成功设计和优化所提出的分离设备至关重要。与开发和改进制造纳米级材料或器件所需的实验技术方面的重大活动和进展形成对比的是，理解纳米级传输现象的框架还不太发达，特别是在具有显著几何限制的情况下，如这里感兴趣的情况，其中通道尺寸与悬浮颗粒的尺寸相当。因此，我们提出了一项合作努力，将关键实验与多尺度建模和模拟相结合，旨在了解具有几何约束的流动条件下颗粒-表面相互作用的主要方面。科学方面：粒子的布朗漂移阻碍了人们想要在流体装置中的特定位置处理特定粒子的应用。这项工作中研究的聚焦方案可以用来克服这些复杂的问题，并可以在芯片实验室设备中广泛使用。在这种背景下，这项工作的潜在扩展是广泛的，因为在流体设备中的粒子操纵领域和在表面性质的主动控制领域中的高活性。教育和推广方面：在我们的项目中，粒子-表面相互作用产生的基本问题，以及利用分子现象用于技术应用的潜在影响，将被纳入为本科生和研究生课程“分子模拟”和“纳米材料中的界面现象”设计的模块，这两个模块目前是参与机构IGERT计划的一部分。这些单元将为学生提供一个明确的例子，说明需要多学科团队来理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，本项目将向这两个机构提供的不同外联和教育方案的本科生和高中生提供实践经验。这些学生将成为多样化研究团队的一部分，因此，他们将为日益跨学科的生物分子和化学工程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，及时向公众展示结果。

National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)Proposal Number: 0731109Principal Investigators: Koplik, JoelAffiliation: CUNY City CollegeProposal Title: Collaborative Research: Separation of nanoparticles using gradient surfaces: multiscale simulations and experimentsThe 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.