Biomedical Engineering Reference
In-Depth Information
When. exposed. to. a. heterobifunctional. streptavidin-NiNTA. linking. molecule,. the. two.
opposing.ends.could.be.linked,.generating.a.protein.nanoring..Additionally,.the.circum-
ference.of.the.nanorings.could.be.dictated.by.controlling.the.length.of.the.DNA.genome.
within.the.M13.phage.and,.hence,.the.capsid.length.(Nam.et.al..2004).
7.3.3 Therapeutics
Nanoengineering.of.M13.for.the.purpose.of.drug.delivery.is.still.in.its.infancy.with.respect.
to.some.of.the.other.viruses.discussed.in.this.chapter..However,.the.ability.to.tether.multi-
ple.peptides.to.the.capsid.exterior.makes.the.M13.bacteriophage.an.excellent.candidate.for.
further.exploration..Recently,.a.cancer.cell-targeting.peptide.was.introduced.on.the.capsid.
protein.and.the.phage.incorporated.into.drug-loaded.liposomes.for.selective.targeting.and.
killing.of.cells.(Ngweniform.et.al..2009,.Wang.et.al..2010).
7.3.4 Photocatalysis and Alternative energy
The.discreet.nanoscale.order.that.viruses.exhibit.can.be.extremely.beneicial.for.applica-
tions.in.light.harvesting,.where.precise.nanoscale.control.of.photosensitizers,.donors,.and.
acceptors.can.have.a.large.impact.on.system.eficiencies..Moreover,.the.one-dimensional.
nature.of.ilamentous.viruses.makes.them.ideal.biological.templates.for.use.in.light.har-
vesting.antenna.systems.
It.has.been.demonstrated.that.modifying.the.pVIII.capsid.protein.to.display.additional.
tryptophan. residues. on. the. capsid. surface,. increases. the. interaction. with. a. photoactive.
porphyrin.. The. result. is. an. increased. energy. transfer. between. the. aromatic. tryptophan.
residues. and. porphyrin. molecules.. This. could. be. observed. by. monitoring. the. emission.
peak.of.the.porphyrin.when.the.samples.are.illuminated.at.the.absorbance.peak.of.trypto-
phan.(Scolaro.et.al..2006)..An.alternative.strategy.uses.carbodiimide.chemistry.to.conjugate.
zinc.porphyrins.to.native.lysine.residues.on.the.pVIII.capsid.protein..Nam.et.al..attached.
approximately.3000.porphyrins.to.each.virus.and.demonstrated.that.the.porphyrin-coated.
phage.exhibited.energy.transfer.and.exciton.migration.along.the.length.of.the.phage.(Nam.
et.al..2010b).(Figure.7.7)..Additional.work.involved.expressing.an.iridium.binding.peptide.
on. the. pVIII. coat. protein.. Zinc. porphyrin-modiied. phages. were. immersed. in. iridium.
hv
FRET
Quenching
Electronic coupling
Pigment
Figure 7.7
(See companion CD for color igure.)
.Energy.transfer.between.porphyrins.coupled.to.the.surface.of.the.M13.
bacteriophage..(Reprinted.with.permission.from.Nam,.Y..S.,.Shin,.T.,.Park,.H.,.Magyar,.A..P.,.Choi,.K.,.Fantner,.
G.,.Nelson,.K..A.,.Belcher,.A..M.,.Virus-templated.assembly.of.porphyrins.into.light-harvesting.nanoantennae..
Journal of the American Chemical Society
.2010b,.132(5),.1462-1463..Copyright.2010.American.Chemical.Society.)
