The Biosynthesis of Anisotropic Nanoparticles - Bionanotechnology: Global Prospects - page 190

(A) Ferritin-like capsules
(B) Bacterial S-layers
(C) Microtubuli,
rhapidosomes,
amyloid fibers,
actin
(D) Viral envelopes
(E) Protein crystals
FIGURE 9.6
The.main.conigurations.of.protein.biotemplates..(A).The.apoferritin.protein.shell.on.the.outside.is.loaded.with.
magnetoferritin.to.produce.magnetic.particles..(B).Bacterial.S-layers.have.been.used.as.templates.for.the.con-
struction.of.two-dimensional.arrays.of.nanoparticles..Protein.molecules.are.shown.as.ovals.and.nanoparticles.
as.spheres..(C).Microtubuli,.rhapidosomes,.amyloid.ibers,.and.actin.have.all.been.employed.as.biotemplates.
for.the.construction.of.nanowires..The.deposited.metal.grains.are.shown.as.black.spheres..(D).The.regularity.of.
viral.envelopes.has.been.exploited.for.biotemplating..(E).The.three-dimensional.array.of.a.protein.crystal.struc-
ture.was.used.to.synthesize.a.nanostructured.protein-hydrogel.complex..Ovals.depict.the.regular.arrangement.
of.protein.molecules;.hydrogel.molecules.are.in.gray.and.it.within.the.voids..(From.Lagziel-Simis,.S.,.et.al.,. Curr.
Opinion Biotechnol. ,.17,.569,.2006..With.permission.).
Similarly. to. the. protein. ferritin,. viruses. have. been. used. in. the. template-directed. syn-
thesis.of.nanostructures..A.typical.example.of.the.use.of.virus.envelopes.(Figure 9.6D).is.
the.use.of.the.tobacco.mosaic.virus.as.a.biotemplate.for.the.synthesis.of.nickel.and.cobalt.
nanowires.a.few.atoms.in.diameter. 61 .Viral.capsids.have.also.been.used.for.the.synthesis.
of.magnetic.virus.particles, 62 .and.gold.cobalt.hybrid.nanowires.have.recently.been.synthe-
sized.on.the.envelope.protein.of.the.M13.phage..These.hybrid.nanowires.were.successfully.
used.as.highly.effective.anodes.in.a.lithium.ion.battery. 53
Using.the.protein-mediated.control.of.crystal.growth.and.the.crystallization.of.gold.as.
a.model.system,.Brown.et.al. 41 .found.that.polypeptides.could.control.the.morphology.of.
the.resulting.gold.crystals.(Figure 9.6E)..Similarly,.Naik.et.al. 63 .randomly.identiied.silver.
binding. peptides. and. demonstrated. the. reduction. of. silver. ions. by. the. peptides,. Slocik.
et.al. 64 .described.the.successful.formation.of.gold.nanoparticles.by.a.tyrosine.tripeptide,.
and.Braun.et.al. 65 .utilized.gold.binding.peptides.of.14-30.amino.acid.repeats.
Nucleic.acids.are.also.ideal.structural.templates,.and.a.variety.of.secondary.structures.
can.be.achieved.using.DNA.and.RNA;.e.g.,.duplexes,.hairpins,.triplexes,.cruciforms,.and.
tetraplexes.can.be.exploited.to.engineer.nanoparticle.organization. 66