Mathematical and numerical model to study two-dimensional free flow isoelectric
focusing |
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Authors: | Kisoo Yoo Jaesool Shim Jin Liu Prashanta Dutta |
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Institution: | 1.School of Mechanical and Materials Engineering, Washington
State University, Pullman, Washington 99164-2920, USA;2.School of Mechanical Engineering, Yeungnam
University, Gyeongsan, Gyeonsanbukdo, South Korea |
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Abstract: | Even though isoelectric focusing (IEF) is a very useful technique for sample concentration and
separation, it is challenging to extract separated samples for further processing. Moreover, the
continuous sample concentration and separation are not possible in the conventional IEF. To overcome
these challenges, free flow IEF (FFIEF) is introduced in which a flow field is applied in the
direction perpendicular to the applied electric field. In this study, a mathematical model is developed for FFIEF to understand
the roles of flow and
electric fields for
efficient design of microfluidic
chip for continuous separation of proteins from an initial well mixed solution. A finite volume based
numerical scheme is implemented to simulate two dimensional FFIEF in a microfluidic chip. Simulation results
indicate that a pH gradient forms as samples flow downstream and this pH profile agrees well with
experimental results validating our model. In addition, our simulation results predict the experimental behavior of
pI markers in a FFIEF microchip. This numerical model is used to predict the separation
behavior of two proteins
(serum albumin and cardiac troponin I) in a two-dimensional straight microchip. The effect of
electric field is
investigated for continuous separation of proteins. Moreover, a new channel design is presented to increase the separation
resolution by introducing cross-stream flow velocity. Numerical results indicate that the separation
resolution can be improved by three folds in this new design compare to the conventional straight
channel design. |
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Keywords: | bioMEMS microfluidics pH phase shifting masks proteins |
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