Microfluidics - Introduction to BioMEMS - page 193

perfected by several groups. For example, Nadine Aubry's group at the New Jersey Institute of
Technology (Newark) has applied out-of-phase sinusoidal voltages to pump the luids into the two
inlets of a Dahleh micromixer, such that the total low rate is kept constant ( Figure 3.93 ).
Recently, Igor Mezic's group has developed a sophisticated version of the Dahleh micromixer
whereby the main low (containing the two solutions to be homogenized) is sheared sideways by
several secondary channels, which are actuated with an oscillating pump at a frequency on the
order of 2 Hz ( Figure 3.94 ). he two luids are mixed within 200 μm in less than 10 ms, which
represents an improvement of ive orders of magnitude over difusion-limited mixing.

Biased sinusoidal pulsing

8.5

1.00e+00
9.38e-01
8.75e-01
8.12e-01
7.50e-01
6.88e-01
6.25e-01
5.62e-01
5.00e-01
4.38e-01
3.75e-01
3.12e-01
2.50e-01
1.88e-01
1.25e-01
6.25e-02

1

Time

-6.5

Y
Z X

0.00e+00

FIGURE 3.93 The.Dahleh.micromixer.driven.with.sinusoidal.pulsing..(From.Ian.Glasgow.and.Nadine.
Aubry,. “Enhancement. of. microluidic. mixing. using. time. pulsing,”. Lab Chip . 3,. 114-120,. 2003..
Reproduced.with.permission.from.The.Royal.Society.of.Chemistry.)

Actuated secondary
channel

Secondary channels

a b

Inlet A

2h

L

Outlet

Main channel

2h

h / 2

3h

300

Particle image
velocimetry

c

Inlet B

Secondary channels

250

200

150

100

Syringe pump

50

Oscillating pump

0 0

100 200 300 400

X (µm)

FIGURE 3.94 Shear. superposition. micromixer.. (From. Frédéric. Bottausci,. Caroline. Cardonne,.
Carl.Meinhart,.and.Igor.Mezic,.“An.ultrashort.mixing.length.micromixer:.The.shear.superposition.
micromixer,”. Lab Chip .7,.396-398,.2007..Reproduced.with.permission.from.The.Royal.Society.of.
Chemistry.)