Collaborative Research: Fundamental Mechanisms of Microfluidic Traveling-Wave Electrophoresis

该项目由数学和物理科学理事会化学司资助。伊利诺伊大学的Aaron Timperman教授和犹他州立大学的Boyd Edwards教授正在研究一种名为微流体行波电泳（TWE）的新型分离方法的基本机制。TWE是一种很有前途的方法，可以降低可能来自生物有机体或环境的样品的复杂性。在对TWE机制的研究中，该团队正在精确地确定TWE是如何工作的，并优化其性能。TWE分离的独特特性使其非常适合其他分离方法无法实现的应用。TWE分离是用非常低的电压（+/-0.5 V）驱动的，比它最近的亲戚微通道电泳小1000到10000倍。这种低电压要求使TWE与现场传感系统高度兼容。TWE在诸如人体医学、法医和药物测试中的生物标记物检测、环境中有毒物质检测以及国土防御威胁物检测等应用中应该证明是有用的。该团队与伊利诺伊州学术大使合作，加强中学生和高中生对STEM研究的接触。采用实验和理论相结合的建模方法，对TWE的机制进行了全面和定量的描述。TWE是一种低频交流电泳分离，其中纵向电场波通过微流体通道传播。TWE的分离机制是独特的：只需改变行波的频率，TWE就可以在分离输运、非分离输运和固定化之间快速切换；而阴离子和阳离子都朝着同一个方向运动。这项工作的目的是充分了解和定量描述行波电泳的基本机制。目标是：1)确定带迁移的机制，2)确定带色散的机制，3)定义分离效率、分辨率和峰值容量的基本方程。实验结果对理论模型的发展具有指导意义，并对推导的基本方程进行了实验验证。这些基本方程为该分离方法与其他分离方法进行定量比较和优化装置设计提供了依据。实验团队包括本科生和研究生。这是一个跨学科的项目，让学生接触分离、理论建模和工程制造。其中包括一个影响初中生和高中生的外展部分，让他们接触STEM学科。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 project is funded by the Chemistry Division of the Mathematical and Physical Sciences Directorate. Professors Aaron Timperman from the University of Illinois and Boyd Edwards from Utah State University are investigating the fundamental mechanisms of a new separation method called microfluidic traveling-wave electrophoresis (TWE). TWE is a promising method for reducing the complexity of samples that may come from biological organisms or the environment. In the investigation of the mechanisms of TWE, the team is determining precisely how TWE works and on optimizing its performance. The unique characteristics of TWE separations make it well-suited for applications that cannot be achieved with other separation methods. The TWE separation is driven with very low voltages (+/-0.5 V) which are 1,000 to 10,000 times smaller than its nearest relative, microchannel electrophoresis. This low voltage requirement makes TWE highly compatible with fieldable sensing systems. TWE should prove helpful in applications such as detection of biomarkers in human medical, forensic, and drug testing, detection of toxic substances in the environment, and detection of threat agents for homeland defense. The team collaborates with the Illinois Academic Ambassadors to enhance exposure of middle school and high school students to STEM research.A combined experimental and theoretical modeling approach is used to provide a thorough and quantitative description of the mechanisms of TWE. TWE is distinct as a low frequency AC electrophoretic separation in which a longitudinal electric field wave propagates through the microfluidic channel. The separation mechanisms of TWE are unique: TWE can rapidly switch between separative transport, non-separative transport, and immobilization simply by changing the frequency of the traveling wave; and both anions and cations move in the same direction. The goal of this work is to fully understand and quantitatively describe the fundamental mechanisms of traveling wave electrophoresis. The objectives are: 1) determining the mechanisms of zone migration, 2) determining the mechanisms of zone dispersion, and 3) defining the fundamental equations of separation efficiency, resolution, and peak capacity. The experimental results guide the development of the theoretical models, and the fundamental equations derived are experimentally verified. These fundamental equations provide a basis with which this separation method can be quantitatively compared with others and inform optimal device design. The experimental team includes both undergraduate and graduate students. This is an interdisciplinary project that exposes students to separations, theoretical modeling, and fabrication in Engineering. An outreach component is included that impacts middle and high school students, exposing them to STEM disciplines.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.