Biomedical Engineering Reference
In-Depth Information
Pre-stressed
ermoplastic
Nanostructures
Heat
1.5 µm
Depos
it ink
Microfluidic Chips
FIGURE 13.1
(See.color.insert.).Ultra-rapid,.low-cost.manufacturing.process.of.nano-integrated.microsystems.
resolution..This.approach.eliminates.the.need.for.expensive.capital.equipment.and.reduces.
the.cost.of.each.chip.to.pennies..We.simply.pattern.at.the.large.scale,.which.is.inexpensive.
and.easy,.and.subsequently.shrink.down.to.the.small.scale..We.use.prestressed.polymer.
sheets.and.leverage.the.inherent.retraction.properties,.which.can.controllably.shrink.fea-
tures.down.to.40%-95%.of.their.patterned.sizes,.depending.on.the.polymer.chain.length.
and.amount.of.extrusion.
27-30
.With.these.tunable.shape.memory.polymers,.we.can.create.
nanostructures. integrated. directly. into. our. microsystems. (Figure 13.1).. This. ultra-rapid.
fabrication.approach.results.in.plastic-based.microluidic.systems.with.integrated.metallic.
nanostructures.for.surface-enhanced.sensing.based.on.surface.plasmon.resonance.(SPR)..
We.have.demonstrated.that.our.integrated.nanostructures.can.signiicantly.enhance.the.
signal.output.of.the.bioassay,.therefore.also.obviating.the.need.for.high-powered.excita-
tion.lasers.and.detector.systems.
31
13.2 FabricationandCharacterizationofNanowrinkles
Metal.wrinkles.are.thin.ilms.of.metal.on.polymer.substrates.that.are.formed.after.the.
metal. buckles. during. the. heating. process.. The. ability. to. fabricate. metal. wrinkles. into.
plastics.has.promising.applications.in.molecular.detection,.optical.devices,.electronics,.
biological.assays,.ilters,.and.sorters.
32-36
.Previous.processes.for.manufacturing.the.wrin-
kles. have. been. tedious,. time-consuming,. and. sometimes. utilize. expensive. microfabri-
cated. molds. or. ion/electron. beam. equipment.. Researchers. such. as. Bowden. et. al.. were.
able.to.achieve.feature.sizes.of.30.µm.after.depositing.metal.onto.a.thermally.expanded.
PDMS.and.cooling.it.down.to.ambient.temperature.
34
.Huck.et.al..utilized.this.technique.
