Biomedical Engineering Reference
In-Depth Information
FIGURE 22.10
Bundle.structure.composed.of.sheaths.of.200-500.nm;.cores.illed.with.10.nm.ibrils.
transported.to.the.Ti.anode,.through.the.load,.and.reintroduced.to.the.original.gold.thin.
ilm..In.this.conformation.the.gold.thin.ilm.essentially.acts.as.the.solid-state.electrolyte,.
shuttling.electrons.back.to.the.photoactive.adsorbents.so.that.the.process.can.start.over.
This.introduces.several.engineering.and.operational.beneits..For.one,.chemical.reduc-
tion,.diffusion,.and.oxidation.of.an.electrolyte.species.are.no.longer.involved,.thus.elimi-
nating. one. potentially. rate-limiting. step.. Additionally,. liquids. sealed. in. enclosed. spaces.
such. as. those. found. in. solar. cells. risk. rupturing. their. containment. as. a. result. of. ther-
mal.expansion.or.evaporation.when.exposed.to.high.temperatures..Finally,.gold.has.been.
shown.to.be.an.ideal.surface.for.protein.adsorption,.promoting.higher.protein.crystalliza-
tion.at.the.electrode.surface,.and.thus.improving.overall.cell.performance.
22.5 ProteinDynamicsatNanoscaleSurfaces
Because.proteins.are.essentially.polymers.self-assembled.into.very.speciic.conformations,.
minute.changes.in.the.conformation.of.these.biopolymer.aggregates.can.lead.to.a.loss.of.
protein. function.
.
This. is. particularly. true. in. antennae. proteins. where. Forster. resonant.
energy. transfer. (FRET)
43
. between. the. chromophore. molecules. is. highly. dependent. on.
spatial.relations..So,.it.is.not.surprising.that.the.foremost.concern.of.BSSCs.is.the.stabil-
ity.of.biological.components.in.the.presence.of.the.solar.cell's.high-energy.environment..
Combining. signiicant. temperature. luxuations,. high. surface. energy. materials,. and. an.
abundance. of. surface. area,. the. solid-state. interface. of. an. exitonic. junction. solar. cell. can.
be.a.hostile.environment.for.proteins..A.keen.understanding.of.the.forces.and.the.result-
ing.protein.folding.dynamics.will.be.a.key.aspect.in.the.future.designs.of.such.biohybrid.
devices,. as. well. as. addressing. unknown. interactions. in. biological. systems. for. efforts. to.
accurately.map.the.effects.of.nanotoxicity.
