Dielectrophoresis - The Nanobiotechnology - page 401

E

20 µm

(a) (b) (c)

(e)

(d)

Figure 17.6
(See companion CD for color igure.) .The.EDEP..(a-c).The.working.mechanism.of.EDEP.generated.from.spatial.
contraction.and.expansion.of.the.low.channel.geometry..(a.and.c:.Reproduced.from. Biophys. J., .83,.Chou,.C.,.
Tegenfelbt,.J.O.,.Bakajin,.O.,.Chan,.S.S.,.Cox,.E.C.,.Darnton,.N.,.Duke,.T.,.and.Austin,.R.H.,.Electrodeless.dielec-
trophoresis. of. single-. and. double-stranded. DNA,. 2170-2179.. Copyright. 2002,. with. permission. from. Elsevier).
b:.Reprinted.with.permission.from.Chou,.C..and.Zenhausen,.F.,.Electrodeless.dielectrophoresis.for.micro.total.
analysis.systems,. IEEE Eng. Med. Biol., .22,.62-67..Copyright.2003,.IEEE.).(d-e).The.working.mechanism.of.EDEP.
generated.from.insulator.post.arrays.immersed.in.low..(Reprinted.with.permission.from.Cummings,.E.B..and.
Singh,.A.K.,.Dielectrophoresis.in.microchips.containing.arrays.of.insulating.posts:.Theoretical.and.experimen-
tal.results,. Anal. Chem., .75,.4724-4731..Copyright.2003.American.Chemical.Society.)

complementary.metal-oxide.semiconductor.in.which.silicon.oxide.is.used.as.the.capacitor.
dielectric.sandwiched.between.a.silicon.substrate.electrode.and.a.metal.gate.electrode),.as.
shown.in.Figure.17.4d..Unlike.other.planar.designs.of.interdigitated.castellation.electrodes,.
it.has.a.vertical.setup.for.the.electrode.pair.with.an.asymmetric.area.and.a.shape.of.a.square,.
circle,.or.ring..The.asymmetric.structural.area.of.its.electrode.pairs.provides.a.local.electric.
ield.gradient.needed.for.DEP.polarization..Most.importantly,.each.electrode.pair.of.this.
electrode.design.can.have.their.own.signal.control.and.can.be.easily.integrated.into.large.
arrays..The.later.can.greatly.increase.the.DEP.trapping.throughput.while.the.former.offers.
convenient.controls.on.each.individual.DEP.unit.in.the.large.array.to.accomplish.various.
particle. actuation. motions. including. trapping,. levitation,. or. even. a. sequence. motions. of.
particle.for.transportation.

17.3.2 Quadruple electrode Structure

Quadruple.electrode.conigurations.(Figure.17.5).are.popularly.used.for.static.DEP,.ROT,.
or. TWD. to. trap. and/or. manipulate. single. or. multiple. particles.. They. usually. have. two.
pairs.of.electrodes.located.at.four.corners.of.cross.shape.geometry.while.the.actual.shape.
of.the.electrodes.varies.with.the.application.needs..For.static.DEP.trapping,.polynomial,.
planar,. or. extruded. electrodes. are. often. used. (Figure. 17.5a. through. c).. Both. p-DEP. and.
n-DEP. can. be. realized. with. this. coniguration. to. capture. particles. either. at. the. center. of.