Electrokinetic sample transport in a microchannel with spatial electrical conductivity gradients.

Studies of the sample transport in a microchannel with the electrical conductivity gradient are critical to develop techniques for on-chip sample transport control. A numerical model presented in this paper, consisting of the electrical potential equation, full Navier-Stokes equation and species conservation equation, is used to simulate sample transport in a microchannel with the consideration of the conductivity gradient. There are two situations studied here, sample pumping (where sample separation is minimized by employing a high-conductivity buffer in the sample region), and sample stacking (where sample separation is expedited by using a low-conductivity buffer as the sample carrier). The effects of applied electrical potential, sample diffusion coefficient and the ratio of conductivity of the driving buffer over the sample carrying buffer are investigated by using the developed model.

[1]  Gwo-Bin Lee,et al.  Multiple injection techniques for microfluidic sample handling , 2003, Electrophoresis.

[2]  H. Andersson,et al.  Microfluidic devices for cellomics: a review , 2003 .

[3]  Chia-Jung Hsu.  Numerical Heat Transfer and Fluid Flow , 1981 .

[4]  Robert S Foote,et al.  Stacking due to ionic transport number mismatch during sample sweeping on microchips. , 2005, Lab on a chip.

[5]  F. Everaerts,et al.  Concentration distributions in free zone electrophoresis , 1979 .

[6]  S. Jacobson,et al.  Integrated microdevice for DNA restriction fragment analysis. , 1996, Analytical chemistry.

[7]  Dongqing Li,et al.  Effects of liquid conductivity differences on multi-component sample injection, pumping and stacking in microfluidic chips. , 2003, Lab on a chip.

[8]  Liqing Ren,et al.  Theoretical studies of microfluidic dispensing processes. , 2002, Journal of colloid and interface science.

[9]  J. W. Parce,et al.  Electrokinetically controlled microfluidic analysis systems. , 2000, Annual review of biophysics and biomolecular structure.

[10]  J. Santiago,et al.  Convective and absolute electrokinetic instability with conductivity gradients , 2005, Journal of Fluid Mechanics.

[11]  L. Fu,et al.  Electrokinetic injection techniques in microfluidic chips. , 2002, Analytical chemistry.

[12]  Yan Li,et al.  Dynamic analyte introduction and focusing in plastic microfluidic devices for proteomic analysis , 2003, Electrophoresis.

[13]  Zhifang Fan,et al.  Miniaturized capillary isoelectric focusing in plastic microfluidic devices , 2002, Electrophoresis.

[14]  David J. Beebe,et al.  Evaluation of a Three-Dimensional Micromixer in a Surface-Based Biosensor† , 2003 .

[15]  G. Bruin,et al.  Recent developments in electrokinetically driven analysis on microfabricated devices , 2000, Electrophoresis.

[16]  Dongqing Li,et al.  A dynamic loading method for controlling on-chip microfluidic sample injection. , 2003, Journal of colloid and interface science.

[17]  J. Santiago,et al.  Instability of electrokinetic microchannel flows with conductivity gradients , 2004 .

[18]  Cheng-Huang Lin,et al.  Sample-stacking techniques in non-aqueous capillary electrophoresis. , 2005, Journal of chromatography. A.

[19]  James C Baygents,et al.  Electrically-driven fluid motion in channels with streamwise gradients of the electrical conductivity , 2001 .

[20]  S. Jacobson,et al.  Computer simulations of electrokinetic transport in microfabricated channel structures. , 1998, Analytical chemistry.

[21]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[22]  Howard H. Hu,et al.  Numerical simulation of electroosmotic flow. , 1998, Analytical chemistry.

[23]  A. van den Berg,et al.  Optimization of an electrolyte conductivity detector for measuring low ion concentrations. , 2002, Lab on a chip.

[24]  Alan P. Morrison,et al.  Development of a microfluidic device for fluorescence activated cell sorting , 2002 .

[25]  John B. Shoven,et al.  I , Edinburgh Medical and Surgical Journal.

[26]  S. Jacobson,et al.  Microchip electrophoresis with sample stacking , 1995, Electrophoresis.

[27]  C. Lunte,et al.  On‐line preconcentration methods for capillary electrophoresis , 2000, Electrophoresis.

[28]  Dongqing Li,et al.  Visualization and numerical modelling of microfluidic on-chip injection processes. , 2003, Journal of colloid and interface science.

[29]  P. Dutta,et al.  Electrokinetic Transport Phenomena in Micro-Fluidics , 2004 .

[30]  Christopher R. Lowe,et al.  Silicon microchambers for DNA amplification , 1998 .

[31]  S. Jacobson,et al.  Computer simulations of electrokinetic injection techniques in microfluidic devices , 2000, Analytical chemistry.

[32]  Rajiv Bharadwaj,et al.  Thousandfold signal increase using field‐amplified sample stacking for on‐chip electrophoresis , 2003, Electrophoresis.