Biomedical Engineering Reference
In-Depth Information
9
The
Biosy
nthesisofAnisotropicNanoparticles
MariekieGericke
BiotechnologyDivision,Mintek,Randburg,SouthAfrica
CONTENTS
9.1. Introduction......................................................................................................................... 181
9.2. Biosynthesis.of.Nanoparticles.......................................................................................... 182
9.2.1. Bacterial.Production.of.Nanomaterials............................................................... 182
9.2.2. The.Use.of.Yeast.in.Nanoparticle.Synthesis....................................................... 183
9.2.3. Nanoparticle.Formation.by.Actinomycetes........................................................ 183
9.2.4. The.Use.of.Fungi.in.Nanoparticle.Synthesis...................................................... 184
9.3. Control.of.Growth.Parameters.to.Manipulate.Nanoparticle.Characteristics............ 186
9.4. Mechanism.of.Biological.Nanoparticle.Synthesis......................................................... 187
9.5. The.Use.of.Templates.for.Nanoparticle.Synthesis......................................................... 189
9.6. Conclusions......................................................................................................................... 191
References..................................................................................................................................... 191
9.1 Introduction
The. synthesis. of. anisotropic. nanoparticles. is. a. rapidly. developing. research. ield. and.
has. received. considerable. attention. over. the. past. few. years.. These. nanoparticles,. which.
include. various. shapes,. such. as. rods,. discs,. triangles,. hexagons,. cubes,. and. nanoshells,.
exhibit.unique.properties,.which.either.strongly.differ.from.or.are.more.pronounced.than.
those.of.symmetric,.spherical.nanoparticles..Their.unusual.optical.and.electronic.proper-
ties,.improved.mechanical.properties,.and.speciic.surface-enhanced.spectroscopies.make.
them.ideal.structures.for.applications.in.photonics,.optical.sensing.and.imaging,.biomedi-
cal. labeling. and. sensing,. catalysis,. and. electronic. devices,. among. others.. The. size. and.
morphology.of.these.nanoparticles.are.critical.in.the.determination.of.these.novel.proper-
ties,.and.with.an.ever-broadening.range.of.applications,.the.controlled.synthesis.of.aniso-
tropic.materials.has.never.been.more.important.
1-4
Various. strategies. have. been. employed. to. synthesize. anisotropic. nanoparticles,. and.
although.some.success.has.been.achieved.in.developing.chemical.and.physical.procedures.
for.the.synthesis.of.anisotropic.nanoparticles,.there.are.still.a.number.of.bottlenecks.and.
challenges.involved.in.the.controlled.production.of.these.materials,.and.to.understanding.
the.shape-guiding.mechanisms.
2,3
Over.the.last.decade.the.utilization.of.biological.systems.such.as.yeasts,.fungi,.bacteria,.
and.plants.to.produce.nanoparticles.has.been.demonstrated.and.has.emerged.as.a.promis-
ing.potential.method.for.the.synthesis.of.anisotropic.metal.nanoparticles..This.is.not.unex-
pected.since.many.organisms,.both.unicellular.and.multicellular,.are.known.to.produce.
181
