Micro electroosmotic chip with surface charge patterning
Electroosmosis (EO) has been applied to drive the sample fluid in many commerical biochips such as the ones made by Caliper Technology and ACLARA Biosciences. Recently, it has been found that the EO chip with surface charge patterning can generate a variety of micro flow pattern such as bi-directional shear flow, micro vortex flow etc. This can be very useful for biofluid flow control and micromixing in advanced biochips.
(a) Packaged micro electroosmotic chip, (b) out-of-plane vortex velocity field generated by the
micro EO chip with surface charge patterning.
Selected reference
W.L.W. Hau, P.K. Leung, Y.-K. Lee, L.M. Lee, Y. Zohar, "Electrokinetically-Driven Micro Mixer with a Novel Surface-Charge Pattern," IEEE Robio 2005 (in press).
L.M. Lee, W.L.W. Hau, Y.-K. Lee, M. Wong and Y. Zohar, "Unsteady In-plane Vortex Motion in a Microchannel Liquid Flow," IEEE MEMS 2005, Miami, FL, USA, pp.734-737, 205.
A.S.W. Ng, W.L.W. Hau, Y.K. Lee and Y. Zohar, "Electrokinetic Generation of Micro Vortex Patterns in a Microchannel Liquid Flow," Journal of Micromechanics and Microengineering, Vol. 14, No. 2, pp.247-255, 2004.
W.L.W. Hau, L.M. Lee, Y.K. Lee, M. Wong and Y. Zohar, "Experimental Investigation of Electrokinetically Generated
In-Plane Vorticity in a Microchannel", Transducer'03 (the 12th Intl. Conf.
on Solid-State Sensors, Actuators and Microsystems), Boston, pp.651-654,
2003.
A. S. W. Ng, W.L.W. Hau, Y.K. Lee and Y. Zohar, "Numerical Simulations of Electrokinetically Generated Micro Vortices in Microchannels," Transducer'03 (the 12th Intl. Conf. on Solid-State Sensors, Actuators and Microsystems), Boston, pp.1887-1890, 2003.
References
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A.J. Bard & L.R. Faulker, Electrochemical Methods, John Wiley & Son, 2001 (QD553.B37)
J.N. Israelachvili, Intermolecular and Surface Forces, Academic Press, 1991 (QD461.I87)
R.J. Hunter, Zeta Potential in Colloid Science: Principles and Applicaitons, Academic Press, 1981