Enhanced capillary electrophoretic and hydrodynamic chromatographic separations on microchip devices using a combination of electrokinetic and hydrodynamic flows

University Of Wyoming, Laramie WY

Investigators

Abstract

0854179 Dutta This NSF award by the Chemical and Biological Separations program supports work by Professor Debashis Dutta at the University of Wyoming to develop micro-/nanofluidic devices that can enhance the resolving power of Capillary Electrophoretic (CE) and Hydrodynamic Chromatographic (HDC) separations using a combination of electrokinetic and pressure-driven flows. In addition, the proposed work will also design a novel HDC separation method for DNA molecules based on their shear-induced migration in a pressure-driven flow field. The development of this method will eliminate the necessity to use analysis columns that have lateral dimensions comparable to the solute diameter in order to realize high-efficiency HDC separations. The Specific Aims described above will be accomplished using micro- and nanofluidic devices developed in the PI's laboratory that can generate a pressure-driven flow on-chip using electrical forces. In the proposed devices, a silicate based sol-gel membrane is used to block electroosmotic flow generated along a channel yielding a pressure-gradient in the system. The resulting pressure-driven flow is then guided to an analysis column to drive or enhance a separation process. It is worth noting that the ability to generate pressure-gradients on-chip in these devices provides a precise and dynamic control over the hydrodynamic flow velocity in the analysis column through minimization of dead volumes. Moreover, because this capability is realized using electrokinetic forces, it allows the generation of pressure-gradients within micro- and nanofluidic networks with equal ease. It is anticipated that the proposed work could also have a broad impact on separations research outside of the CE and the HDC techniques. This is because the micro-pump presented here is easy to fabricate and simple to integrate to micro-/nanofluidic separation systems compared to other designs described in the literature. This aspect of the proposed micro-pump could make it attractive for other laboratories to adopt it for their own research. Further, the ability of the proposed devices to generate hydrodynamic flows in micro- and nanofluidic ducts with equal ease makes it a valuable research tool for not only miniaturizing existing pressure-driven separation methods but also studying new separation schemes that rely on a pressure-driven flow field in micro-/nanochannels. Finally, the proposed work will establish an inexpensive and simple procedure for fabricating low resistance and durable silicate based sol-gel membranes in micro-/nanochannels that can be employed under a wider range of assay conditions compared to polymer based membranes commonly used today. While advances in micro-/nanoscale science are revolutionizing the way we understand our world today, the integration of this knowledge into undergraduate and graduate education has been slow. The problem is particularly prominent in states like Wyoming where the development of high tech industries has been well below the national average. However, with increases in the application of nanoscience and nanotechnology to various sectors of the Wyoming economy there is a growing demand on training future workforce in these scientific areas. As the only four-year college in the State of Wyoming, the University of Wyoming (UW) carries the primary responsibility for providing the required infrastructure to meet these demands. The work described in this proposal will help to address this problem by providing educational and research experience to undergraduate and graduate students in applying nanoscience and nanotechnology to important areas of basic and applied research, such as the specific projects described here for improving the resolving power of CE and HDC methods. Besides training graduate and undergraduate students, the PI proposes three additional educational activities aimed at disseminating the results of the research to a broad range of audiences, as well as directly involving high school students in research activities. This will include incorporating proposed CE and HDC separations methods into a graduate level chemistry course at UW, and initiating a summer research apprentice program for high school students. At the same time, the PI will also develop an outreach program with the Central Wyoming College (CWC) that has about 20% Native American and 80% first-generation college student population to broaden the participation of minorities and underprivileged communities.