Biomedical Engineering Reference
In-Depth Information
not.easily.release.primary.particles.under.normal.conditions.(Yokel.and.Macphail.2011)..
Some.reports.of.ield.measurements.show.that.the.airborne.nanomaterials.in.occupational.
settings.are.most.commonly.200-400.and.2000-3000.nm.in.diameter.(Seipenbusch.et.al..
2008,.Brouwer.2010)..The.agglomeration.of.nanomaterials.may.inluence.the.absorption.of.
an.organism,.while.the.agglomeration.situation.within.the.body.will.usually.dominate.any.
toxic.effects..Temporary.organ.injury.in.the.lungs.and.liver.has.been.reported.due.to.delayed.
clearance.of.agglomerated.MWCNTs.in.mice,.while.the.well-dispersed.ones.formed.fewer.
aggregates.in.the.lungs.and.liver,.and.seemed.to.be.easily.eliminated.(Methner.et.al..2007)..
Persistent. accumulation. of. agglomerated. MWCNTs. in. the. lungs. caused. inlammatory.
responses.while.the.well.suspended.ones.did.not..Highly.agglomerated.SWCNTs.caused.
more.serious.toxic.effects.on.glial.cells.in.both.the.peripheral.and.central.nervous.system.
derived. cultures. as. compared. with. better-dispersed. SWCNTs. (Belyanskaya. et. al.. 2009)..
In.estimation.of.the.toxicology.of.nanomaterials,.the.extent.of.agglomeration/aggregation.
should.be.taken.into.account.in.the.characterization.process.
27.2.4 Chemical Composition and Purity and impurities
The. chemical. composition,. in. terms. of. elemental. composition. and. chemical. structure,.
is. an. intrinsic. property. of. all. materials.. With. the. development. of. nanotechnology,.
there. are. an. abundant. amount. of. different. chemical. compositions. of. nanomaterials..
Nanoparticles.relevant.to.nanobiotechnology.may.roughly.comprise.four.categories.by.
their.chemical.composition:.(1).carbon.nanomaterials.(e.g.,.carbon.nanotubes,.nanowires,.
nanocantilevers,.graphene,.and.fullerenes),.(2).metallic.and.metallic.oxide.materials.(e.g.,.
gold.or.silver.nanoparticles,.magnetic.nanoparticles,.QDs,.titanium.dioxide,.iron.oxide),.
(3).silicon.nanomaterials.(silicon.or.silica.nanoparticles),.and.(4).organic.nanomaterials.
(e.g.,. DNA,. polymers,. polymeric. micelles,. liposomes,. or. nanoparticles. prepared. from.
polymers.or.lipids)..Some.nanomaterials.can.exhibit.a.hybrid,.“core-shell”.structure.such.
as. the. semiconductor. nanocrystal. QDs,. with. biomolecular-immobilized. nanomaterials.
as. the. nanobiotechnology. products.. At. present,. there. is. a. lack. of. delicate. data. reports.
and. well-designed. screen. techniques. for. the. nanotoxicological. comparison. of. widely.
used. and. variously. composed. nanomaterials.. Raw. nanotubes,. especially. commercial.
products,. usually. contain. signiicant. impurities. such. as. inert. synthesis. support. (silica,.
alumina). and. metal. catalysts. (iron,. cobalt,. nickel),. which. come. from. the. large-scale.
production. procedures,. post-fabrication. and. post-puriication. treatments.. There. is. a.
great.deal.of.evidence.showing.that.the.impurities.in.CNT.materials.will.substantially.
contribute. to. increased. toxicity. through. induction. of. oxidative. stress. (Pulskamp. et. al..
2007,.Ge.et.al..2011b).
27.2.5 Surface Modification and Surface Charges
Surface. modiication. of. nanoparticles. also. plays. an. essential. role. in. changing. the.
physicochemical. and. surface. properties. of. nanomaterials.. Surface. modiications. can. be.
utilized.to.reduce.the.material.toxicity,.increase.the.solubility,.enhance.biocompatibility,.
and.to.prevent.their.aggregation.in.solutions.(Yan.et.al..2011)..The.most.noticeable.example.
is.probably.that.of.fullerenes..It.has.been.shown.that.signiicant.differences.in.toxicity.and.
biological.function.exist.between.the.conventional.hydrophobic.fullerenes.and.the.surface.
modiied.hydrophilic.ones.(Yin.et.al..2009,.Liu.et.al..2009b)..We.investigated.the.inluence.
of.surface.coatings.on.the.cellular.uptake.and.the.cytotoxicity.of.gold.nanorods.(Au.NRs),.
and.found.that.the.cellular.uptake.of.these.Au.NRs.is.highly.dependent.on.their.surface.
