Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
Figure 17.4
(See companion CD for color igure.)
. Classic. castellated. DEP. electrode. conigurations.. (a). A. single. layer..
(b). A. 2D. interdigital.. (c). A. double-layer. combing. electrode. coniguration.. (d). A. CMOS-like. concentric. elec-
trode.coniguration.with.an.asymmetric.area.and.a.square.shape.
early. DEP. research.. Due. to. the. lack. of. precise. dimension. control. during. fabrication,. the.
relative. position. of. these. pin-wire. electrodes. is. very. large. (e.g.,. several. millimeters).. In.
consequence,.a.high.electric.voltage.is.generally.required.to.attain.a.suficient.DEP.force.to.
trap.or.manipulate.particles..The.recent.advance.in.microfabrication.technologies.greatly.
facilitates.the.emergence.of.smaller.and.more.sophisticated.DEP.electrode.conigurations..
It.helps.produce.more.intense.electric.ield.gradients.with.a.very.low.voltage.(e.g.,.several.
volts). to. carry. on. DEP. trapping. with. reduced. side. effects. (e.g.,. water. electrolysis).. The.
difference. in. the. DEP. forces. exerting. on. various. particles. can. also. be. enhanced. when.
choosing.appropriate.electrode.dimensions.and.geometry..This.leads.to.great.improvements.
in. the. separation. or. sorting. eficiency. of. DEP.. Some. classical. DEP. electrode. designs. are.
discussed.in.Section.17.3.and.shown.in.Figures.17.4.through.17.7.
17.3 DEP Electrode Designs and Derivates
17.3.1 Castellated electrode Structures and Their Derivates
The. common. DEP. electrode. conigurations. include. the. simple. pin-plane. electrode. pair.
(or. cusped. electrode. coniguration). and. other. microfabricated. electrode. arrays. such. as.
comb,. parallel,. and. concentric. designs. with. different. unit. geometries. (e.g.,. circle. and.
square)..Among.these.designs,.the.comblike.coniguration.(or.castellation.coniguration).
is.the.most.widely.adopted.format.in.many.DEP.microdevices..This.attributes.to.the.clear.
viewing.windows.it.offers.for.conveniently.visualizing.the.real-time.particle.motions.and.
