Electrokinetic Flow and Micromixer
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Introduction The manipulation of
bio-particles like cells, DNA, and proteins is important for biological and
medical research. The term AC electrokinetics refers to the movement of
either particles or fluid by using AC electric fields, such as
dielectrophoresis (DEP) and AC electro-osmosis (AC EOF). We have been
developing a variety of novel designs and applications for manipulating
bio-particles in microfluidics for years, for example, trapping, sorting,
pumping, micromixer, cell patterning, and tissue engineering. A novel ac
electrokinetic microfluidic driver based on alternating current
electro-osmosis flow induced by asymmetrically
capacitance/chemistry-modulated microelectrode arrays has been successfully
developed and demonstrated. Asymmetric capacitance modulation (ACM) is made
of comb electrode arrays and parts of individual electrode surfaces are
modulated/deposited with a SiO2 dielectric layer. This proposed design can be
utilized to shift the optimal operation frequency of maximum velocity to a
higher frequency to minimize electrolytic bubble generation and enhance
micropumping performance. The maximum pumping velocity at the applied
potential of 10 Vpp in
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We successfully demonstrated a microfluidic mixer that takes
advantage of field-effect control to dynamically manipulate local flow field
to highly enhance mixing effect in microchannel. The influences of buffer pH,
electrolyte concentration, and radial voltage on the ζ-potential, and
the flow field analysis with nonuniform ζ-potential have been studied
and characterized. The work reported in our group is considered as the first
time temporal/spatial ζ-potential modulation for microfluidic mixer
applications.
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Selected Publication |
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[1] Ching-Te Kuo
and Cheng-Hsien Liu, “A Bubble-Free AC Electrokinetic Micropump Using
The Asymmetric Capacitance-Modulated Microelectrode Array for Microfluidic
Flow Control,” Journal of MicroElectroMechanical Systems 18 (1), pp. 38-51, 2009 [2] Hsin-Yu Wu, and Cheng-Hsien Liu,
“A Novel Micromixer,”
Sensors and Actuators A: Physical, Volume 118, Issue 1 , 31 January 2005,
pp. 107-115 (Research
Highlighted by Lab on a Chip,
2005, 5(5) , 370
– 373) |
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