Biomedical Engineering Reference
In-Depth Information
B
A
On glass
On wrinkles
200
100
On glass
255
0
0
10
20
30
Position (µm)
10 µm
0
1.0
On wrinkles
0.5
On glass
On
wrinkles
0.0
0
2
4
6
8
10 µm
Time (ns)
FIGURE 13.8
(See.color.insert.).(A).Wide-ield.epiluorescence.images.of.dyes.on.glass.plate.(top).and.uniaxial.wrinkles.(bot-
tom)..(B).The.corresponding.intensity.proiles.along.the.arrows.in.(A).(top).and.luorescence.lifetime.measure-
ments.of.dyes.on.a.glass.plate.(top.line).and.wrinkles.(bottom.line).(bottom).
LOC.devices.can.be.rapidly.created..In.particular,.the.nanowrinkles.provide.the.ability.for.
the.metallic.nanostructures.to.be.used.for.MEF-based.sensing.applications.
To.demonstrate.the.utility.of.the.wrinkles.for.POC.technology,.dye.molecules.were.dis-
solved.in.polymer.solution.and.spin.coated.on.the.uniaxial.gold.wrinkles..Furthermore,.
parallel.to.the.direction.of.the.wrinkles,.there.were.many.hot.spots,.which.indicated.a.ive-.
to.sevenfold.enhancement.relative.to.glass.(Figure 13.8A).
In.SPR,.the.luorescence.enhancement.is.accompanied.by.a.decrease.in.the.luorescence.
lifetime..In.order.to.conirm.that.the.enhancement.was.due.to.plasmon.effects.as.opposed.
to. aggregation. of. the. dyes,. luorescence. lifetime. measurements. were. performed. with. a.
confocal.microscope..With.a.homemade.confocal.microscope,.the.average.lifetime.of.the.
luorescence.dye.was.measured.at.1/10.less.than.the.average.lifetime.of.the.glass,.suggest-
ing.that.the.enhancement.resulted.from.strong.interactions.between.the.luorophore.and.
surface.plasmons.(Figure 13.8B).
Although.the.gold.wrinkles.exhibited.only.a.moderate.enhancement.of.luorescent.signal.
over.glass,.the.enhancement.could.be.improved.in.several.ways,.such.as.the.utilization.of.
bimetallic.ilm.instead.of.gold.ilm.alone..During.the.past.decade,.most.of.the.MEF-based.
immunoassays.have.been.developed.on.a.single.metal.ilm.such.as.gold.or.silver..However,.
evidence. has. shown. that. bimetallic. nanostructures,. comprised. of. gold. and. silver,. dem-
onstrate.stronger.surface.plasmon.resonance.(SPR).effects.than.single.pure.metal.
41,68
.The.
multimetallic. alloy. and. core-shell. nanostructures. have. remarkable. catalytic,. electronic,.
