Biomedical Engineering Reference
In-Depth Information
0.6
20
0.4
10
Im (
m
)
(b)
0.2
-0
0.0
-10
(a)
(c)
TWD window
-0.2
-20
-0.4
-30
Re (
m
)
T cell
monocyte
-0.6
-40
-0.8
3
-50
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8
3.5
4
4.5 5.5
Log frequency (Hz)
5
6
6.5
7
7.5
8
(c)
Low frequency (Hz)
(d)
(e)
Figure 17.13 (continued)
(See companion CD for color igure.)
.Traveling-wave.dielectrophroesis.applications..(c.and.d).The.simulated.
frequency. spectrum. of. the. Re(
K)
. and. Im(
K
). (c). and. TWD. velocity. (d). for. human. monocytes. and. T. cells. sus-
pended.in.an.aqueous.medium.of.conductivity.40.mS/m..(e).A.microscopic.image.of.separating.these.two.types.
of.cells.using.superposition.TWD.with.T.cells.traveling.to.the.left.and.monocytes.toward.right..(Reproduced.
with.permission.from.Pethig,.R.,.Talary,.M.S.,.and.Lee,.R.S.,.Enhancing.traveling-wave.dielectrophoresis.with.
signal.superposition,.
IEEE Eng. Med. Biol.,
.23,.43-50,.Copyright.2003,.IEEE.).
the.electrode.array.(Morgan.et.al..1997)..It.has.been.successfully.used.to.separate.viable.yeast.
cells.from.dead.cells.(Talary.et.al..1996),.white.blood.cells.from.erythrocytes.(Green.et.al..1997),.
trophoblast.or.cervical.carcinoma.cells.from.peripheral.blood.cells.(Cheng.et.al..1998;.Chan.
et.al..2000),.and.breast.cancer.cells.from.T.lymphocytes.(Wang.et.al..2000)..The.resolution.and.
purity.of.such.TWD.fractionation.could.be.further.enhanced.by.imposing.more.than.one.set.
traveling-wave.signals..These.signals.are.imposed.on.the.same.electrodes.simultaneously,.
but. with. various. frequencies. and/or. amplitudes.. With. multiple-signal. superposition,.
particles.can.be.guided.to.transport.in.different.directions..A.successful.example.was.given.
by.separating.T.cells.and.monocytes,.as.shown.in.Figure.17.13c.through.e..In.this.example,.
