Single Molecule Electrophoresis using Nanochannel Columns Fabricated in Thermoplastics

凭借这一奖项，化学部门的化学测量和成像项目以及国际科学与工程办公室的全球风险投资基金正在支持北卡罗来纳大学教堂山分校的史蒂文·a·索珀教授开发利用塑料基柱进行纳米级分离（如电泳）的新见解。活动包括：了解使用印迹技术在塑料中生产纳米柱的技术（与生产DVD磁盘的技术相同），修改塑料的表面特性，最后，使用纳米尺寸的塑料柱进行具有独特操作特性的分离。更广泛的影响部分是通过纳米级电泳在许多引人注目的领域的应用效用来证明的，例如DNA或RNA测序，它可以提供由环境影响引起的DNA/RNA分子序列内容变化的信息，识别生物病原体，和/或寻找菌株特异性细菌或病毒感染。该项目团队由北卡罗来纳大学（美国）和韩国蔚山国家科学技术研究所（UNIST）的研究人员组成，他们已经建立了富有成效的研究合作。参与该项目的北卡罗来纳大学研究生将在UNIST工作12个月，以实现该合作项目的具体目标，利用UNIST的研究基础设施和专业知识，体验真正的全球研究环境。该项目采用多学科方法，包括转录组学、RNA/DNA测序和DNA表观遗传序列变异检测，以开发使用纳米柱的单分子电泳领域。所采用的柱是不寻常的，因为它们包含纳米尺寸（200纳米）的宽度和深度的纳米通道，但长度为50微米。这些是用纳米压印光刻技术在热塑性塑料中制造的。通过监测适当制备的靶标的运输来研究小分子和生物聚合物的电泳；目标被标记为荧光标记，因此可以使用粒子跟踪和荧光显微镜进行纵向运动或超分辨率荧光成像来确定横向电迁移来监测传输动力学。在纳米通道上调用了一系列表面修饰，以了解表面电荷密度和这些修饰的均匀性对单分子输运动力学的影响。虽然这些修饰策略已在微通道中得到证实，但它们尚未在纳米通道中得到证实。这两种分子类型的传输都是使用新格式的“超分辨率”显微镜进行的，旨在实现前所未有的灵敏度、空间和时间分辨率。该技术还可以帮助阐明在柱尺寸与德拜长度相似的情况下的电动输运性质。

With this award, the Chemical Measurement and Imaging Program of the Division of Chemistry as well as by the Global Ventures Fund of the Office of International Science and Engineering is supporting Professor Steven A. Soper of the University of North Carolina, Chapel Hill to develop new insights into the use of plastic-based columns for nanoscale separations, such as electrophoresis. Activities include: understanding techniques to produce nano-columns in plastics using imprinting (the same technique used to produce DVD disks), modifying the surface properties of plastics and finally, using plastic columns with nanometer dimensions to undertake separations with unique operating characteristics. The broader impacts are demonstrated in part through the application utility of nanoscale electrophoresis in a number of compelling areas such as DNA or RNA sequencing, which can provide information on variations in the sequence content of a DNA/RNA molecule induced by environmental effects, identifying biopathogens, and/or looking for strain-specific bacterial or viral infections. The project team is comprised of researchers at the University of North Carolina (USA) and at Ulsan National Institute of Science and Technology (UNIST) in South Korea, who have established a productive research collaboration. UNC graduate students participating in this project will spend 12 months at UNIST to work on specific aims of this collaborative project, taking advantage of the research infrastructure and expertise at UNIST and experiencing a truly global research environment.This project takes a multi-disciplinary approach that includes transcriptomics, RNA/DNA sequencing, and detection of epigenetic sequence variations in DNA to develop the area of single-molecule electrophoresis using nanometer columns. The columns that are employed are unusual in that they contain nanochannels with nano-dimensions (200 nm) in width and depth, but lengths of 50 µm. These are fabricated in thermoplastics using nanoimprint lithography. The electrophoresis of both small molecules and biopolymers are investigated by monitoring the transport of the appropriately prepared targets; the targets are labeled with fluorogenic tags so that the transport dynamics can be monitored using particle tracking and fluorescence microscopy for longitudinal motions or super-resolution fluorescence imaging for determining transverse electromigration. A host of surface modifications are invoked on the nanochannels to understand the effects of surface charge density and the homogeneity of these modifications on the transport dynamics of single molecules. While these modification strategies have been demonstrated in microchannels, they are yet unproven in nanochannels. The transport of both molecule types are undertaken using new formats of 'super-resolution' microscopy that aims to achieve unprecedented sensitivity, and spatial and time resolution. The technique may also help to elucidate electrokinetic transport properties in the case where column dimensions are similar to the Debye length.