Dispersion in Capillary Electrophoresis Due to Sample Induced Modification of the Electroosmotic Flow

前言：CTS-0330604PRINCIPAL调查员：SANIPIP GHOSALINT：西北大学毛细管电渗流电泳仪由于样品诱导的修饰而分散在生物研究中是仅次于显微镜的重要分析工具。它最常见的应用是在“凝胶电泳法”中，样品在强电场中通过多孔介质迁移，由于其不同成分的迁移率不同而分离成一系列带。就像跑道上跑步者的快照一样，这种带状图案提供了一个签名或指纹，用于识别样本的化学成分。如果不是让样品通过凝胶的微孔迁移，而是在微毛细管(直径10到100微米)的一端注入，可以实现更快的分离，分辨率更高，使用的样本量要少得多，可能是纳米升。这种技术被称为“毛细管电泳法”(CE)。如果毛细血管是刻在玻璃或硅晶片上的微通道，那么整个生化程序就可以被微型化成“微流控芯片”。本研究的目的是利用流体流动和扩散的基本方程，了解样品沿CE系统微通道移动时的浓度分布是如何演变的。正如显微镜的质量取决于其光学系统的分辨率一样，毛细管电泳法的优值系数取决于样品成分的浓度峰的狭窄程度。对谱带展宽机制的基本理解将导致以下结果：(1)提出新的设计方案，以“突破”可检测到的浓度的小和可解决的分子结构差异的微妙之处，(2)量化最佳可达到的分辨率极限，以及(3)使用本项目试图提供的预测工具来评估潜在的新设计。更广泛的影响包括研究生的培训和成果的传播。此外，PI还将收集和整理成一本电子《流体运动相册》，说明微观尺度上的流体流动。这将由PI在本科生和研究生水平的流体课程中使用，也将提供给研究和教育界。这笔拨款是在NSF数学科学优先领域下资助的。

ABSTRACTPROPOSAL NO.: CTS-0330604PRINCIPAL INVESTIGATORS: SANDIP GHOSALINSTITUTION: NORTHWESTERN UNIVERSITYDispersion in Capillary Electrophoresis due to sample induced modification of the Electroosmotic flow Electrophoresis is an important analytical tool in biological research, second only to the microscope. Its most familiar implementation is in "gel electrophoresis" where the sample migrates through a porous medium in a strong electric field and separates into a series of bands due to differences in the migration rates of its various components. Like a snapshot of runners on a racetrack, this pattern of bands provides a signature or fingerprint for identifying the chemical composition f the sample. If instead of having the sample migrate through the micro pores of the gel, it is injected at one end of a micro-capillary (10 to100 micron diameter), faster separation can be achieved, at a higher resolution and using a much smaller quantity of the sample, perhaps nanoliters. This technique is known as "capillary electrophoresis" (CE). If the capillaries are micro-channels etched on a glass or silicon wafer, entire biochemical protocols can be miniaturized into 'microfluidic chips'. This research is aimed at understanding how the concentration distribution of the sample evolves as it moves down the micochannel of a CE system, by using the basic equations of fluid flow and diffusion. Just as the quality of a microscope is determined by the resolving power of its optics, the figure of merit of a CE system is in the narrowness of the concentration peaks of the sample constituents. Fundamental understanding of the mechanisms of band broadening will result in the following: (1) suggest new designs to "push the envelope" on the smallness of concentrations that can be detected and subtleties in differences in molecular structure that can be resolved, (2) quantify the best achievable resolution limits, and (3) evaluate potential new designs using the predictive tools that this project seeks to provide. The broader impacts include the training of a graduate student and dissemination of results. In addition, the PI will collect and collate into an electronic "Album of Fluid Motion" images illustrating fluid flow on a micro-scale. This will be used by the PI in undergraduate and graduate level fluids classes and would also be made available to the research and educational community. This grant was funded under the NSF Math Sciences Priority Area.