CAREER: Capillary Electrophoretic Mobility Spectrometry - A Solution Phase Analog to Ion Mobility Spectrometry

测量分子结构的能力是理解其行为的关键，比如化学物质如何移动，以及它们为什么与其他分子和自身相互作用。在研究包含成百上千个原子的复杂分子（如生物分子）时，创造新的测量方法来提供这些问题的答案尤为重要。人们对蛋白质非常感兴趣，因为它们在分子水平上的行为受到环境的强烈影响，而环境往往在快速的时间尺度上发生变化。从长远来看，开发基础科学工具，深入了解蛋白质行为，可以为影响生物体健康的因素带来新的视角。田纳西大学诺克斯维尔分校的克里斯托弗·贝克博士开发了一种技术，可以在蛋白质的天然环境中对其结构进行前所未有的高速测量。在这个项目中，一种叫做毛细管电泳迁移率光谱法的新工具可以同时测量极小体积水溶液中的蛋白质大小和离子电荷。该项目得益于三维打印技术的发展，可以创建精确的测量工具。教育外展活动通过将研究主题纳入与中学科学-技术-工程-数学（STEM）教育者合作创建的课程，扩大了项目的影响。这种合作有助于资源有限环境下的教育工作者实现共同核心数学和下一代科学标准中概述的学习目标。教育推广计划侧重于设计和使用动手体验式学习项目，包括实用科学测量设备的三维打印和难以观察的化学性质和事件的计算机辅助模拟。通过该奖项，化学测量和成像项目资助了田纳西大学诺克斯维尔分校的Christopher Baker博士，以开发和整合毛细管电泳（CE）中的两种多探测器策略，从而实现一种称为毛细管电泳迁移率光谱（CEMS）的新技术。蛋白质结构评价是动态生物系统中蛋白质选择性检测方法发展的高度特异性推动力。核磁共振波谱学和x射线晶体学提供了极好的结构分辨率，但需要相对大量的高纯度蛋白质，这对于许多分析来说可能是不可能的。离子迁移率谱法（IMS）作为结构表征和选择性检测的工具正在兴起，但作为一种气相离子分析技术，IMS表征的是影响蛋白质构象的非天然条件下的蛋白质。毛细管电泳（CE）是一种与IMS高度相似的分离技术，但CE是在溶液中进行的。不幸的是，由于有害的分子间相互作用和溶液环境的动态特性，CE的结果不能像IMS的结果那样直接解释。CEMS基于傅里叶变换CE （FT-CE）和Taylor色散分析（TDA）的在线集成，前者大大提高了传统CE的分辨率，后者可以直接和无需校准地测量流体动力半径。改进的分辨率和对结构描述属性的直接观察是IMS和CE之间的关键区别因素，因此，FT-CE与TDA的集成可以在解决方案阶段实现类似IMS的分析。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。

The ability to measure the structure of molecules is key to understanding their behavior, such as how chemical species move and why they interact with other molecules and themselves. Creating new measurement methods that provide answers to these questions is especially important when studying complex molecules containing hundreds and thousands of atoms, such as biological molecules. Of great interest are proteins, because their behavior at the molecular level is strongly influenced by their environment, which often changes on a rapid time scale. From a long-term outlook, developing basic science tools that offer insight into protein behavior can lead to new perspectives on factors that impact the health of organisms. Dr. Christopher Baker at the University of Tennessee Knoxville develops technologies that afford unprecedented, high-speed measurements of the structures of proteins in their native environment. In this project, a new tool called capillary electrophoretic mobility spectrometry enables the simultaneous measurement of protein size and ionic charge in extremely tiny volumes of aqueous solution. This project is enabled by developments in 3-dimensional printing to create precision measurement tools. The educational outreach activities broaden the impact of the project by integrating research topics into curricula created in collaboration with middle school science-technology-engineering-mathematics (STEM) educators. This collaboration helps educators in resource-limited environments meet learning objectives outlined in Common Core Math and Next Generation Science standards. The educational outreach program focuses on the design and use of hands-on experiential learning projects and include 3-dimensional printing of practical scientific measurement devices and computer-aided simulation of difficult-to-observe chemical properties and events. With this award, the Chemical Measurement and Imaging Program is funding Dr. Christopher Baker at the University of Tennessee Knoxville to develop and integrate two multi-detector strategies in capillary electrophoresis (CE) to enable a new technology termed capillary electrophoretic mobility spectrometry (CEMS). Protein structure evaluation is a highly specific motivating force behind the development of methods for the selective detection of proteins in dynamic biological systems. Nuclear magnetic resonance spectroscopy and X-ray crystallography offer excellent structural resolution, but require relatively large quantities of highly purified proteins, which may be impossible for many analyses. Ion mobility spectrometry (IMS) is emerging as a tool for structural characterization and selective detection, but as a gas-phase ion analysis technique, IMS characterizes proteins under non-native conditions that influence protein conformation. Capillary electrophoresis (CE) is a separation technique highly analogous to IMS, however CE is performed in the solution phase. Unfortunately, the results of CE cannot be interpreted as straightforwardly as those of IMS, due to deleterious intermolecular interactions and dynamic properties of the solution environment. CEMS is based on the online integration of Fourier transform CE (FT-CE), which dramatically improves resolution over conventional CE, and Taylor dispersion analysis (TDA), which enables the direct and calibration-free measurement of hydrodynamic radii. Improved resolution and direct observation of structurally-descriptive properties are the key distinguishing factors between IMS and CE, and therefore, the integration of FT-CE with TDA may enable IMS-like analyses in the solution phase.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.