Nanotoxicity - The Nanobiotechnology - page 612

isomers.in.the.cells.increased.after.the.treatment.with.nanoparticles.of.SiO 2 .(15.nm),.Fe 2 O 3 .
(30.nm),.Al 2 O 3 .(13.nm),.TiO 2 .(40.nm),.and.ZnO.(70.nm).(Liu.et.al..2010)..It.has.been.veriied.
that.the.F 2 -isoprostane.level.in.urinary.and.plasma.correlates.with.the.disease.incidence.of.
the.coronary.artery.(Davies.and.Roberts.2011).
QDs. have. been. developed. for. a. broad. range. of. applications. in. bioimaging. and. drug.
delivery.based.on.various.research.of.in.vivo.physiological.behavior.of.these.nanoparticles.
(Qu. et. al.. 2011).. QDs. are. generally. introduced. into. blood. circulation. by. injection,. and.
thus. directly. exposed. to. vascular. endothelial. cells.. The. mercaptosuccinic. acid. capped.
CdTe. QDs. were. proven. to. have. potential. vascular. endothelial. toxicity. in. an. in. vitro.
study,. which. not. only. impaired. cell. mitochondria. but. also. exerted. endothelial. toxicity.
through.the.activation.of.the.mitochondrial.death.pathway.and.induction.of.endothelial.
apoptosis.(Wang.et.al..2010b,.Umezawa.et.al..2011)..Our.recent.work.on.SWCNTs.showed.
endothelial. dysfunction. in. pulmonary. circulation. and. peripheral. vascular. thrombosis.
after.intratracheal.instillation.of.SWCNTs.(Ge.et.al..2011c)..An.in.vitro.study.using.human.
umbilical.vein.endothelial.cells.showed.that.MWCNTs.enter.cells.rapidly,.distribute.in.the.
cytoplasm.and.intracellular.vesicles,.thereby.inducing.morphological.changes..Exposure.
to. MWCNTs. could. reduce. viability. by. inducing. apoptosis. and. causing. DNA. damage..
MWCNTs. also. affected. cellular. redox. status,. e.g.,. increasing. ROS. and. malondialdehyde.
(MDA). levels,. as. well. as. altering. superoxide. dismutase. (SOD). activity. and. glutathione.
peroxidase.(GSH-Px).levels..This.demonstrated.that.MWCNTs.could.induce.cytotoxic.and.
genotoxic.effects.probably.through.oxidative.damage.pathways.in.cells.(Guo.et.al..2011)..
In. vivo,. MWCNTs. have. been. reported. to. be. able. to. transport. through. blood. circulation.
and.cause.extra.pulmonary.toxicities.on.other.organs.including.the.liver.and.kidney.after.
pulmonary.exposure.(Reddy.et.al..2010).
The.preliminary.results.imply.that.all.nanoparticles.should.be.considered.to.have.the.poten-
tial. to. induce. adverse. impacts. on. cardiovascular. events. such. as. thromboembolic. disease;.
many.further.studies.on.diverse.manufactured.nanoparticles.are.needed.to.clarify.how.the.
nanoparticles.in.the.blood.would.induce.cardiovascular.diseases..We.also.should.pay.much.
attention.to.the.altered.properties.of.the.nanosurface.and.nano-size,.which.may.greatly.alter.
the.ways.and.consequences.of.interactions.between.nanoparticles.and.bio-interfaces.in.vivo.
27.4.3 Central Nervous System
The.blood-brain.barrier.(BBB).is.a.specialized.system.that.separates.blood.from.cerebrospinal.
luid..It.consists.of.endothelial.cells.connected.by.complex.tight.junctions,.which.restrict.
the.access.of.outer.compounds.to.the.brain..It.has.been.shown.in.most.exposure.detections.
that. insoluble. nanomaterials. either. poorly. entered. the. brain. or. were. not. detected.. In.
contrast. to. the. accumulation. in. other. tissues,. the. concentration. of. nanomaterials. in. the.
brain.was.orders.of.magnitude.lower..When.a.molecule.tries.to.enter.the.nervous.system,.
it.usually.must.pass.through.cell.membrane.of.endothelial.cells.rather.than.the.complex.
tight. junctions. between. endothelial. cells.. It. has. been. shown. that. nanoparticles. without.
a. surfactant. coating. are. mainly. swallowed. by. phagocytes. and. are. thus. unable. to. reach.
the. brain;. therefore,. surface. modiications. of. nanoparticles. are. currently. being. intensely.
studied.for.nanomedical.applications.in.diagnosis.and.therapy..Some.surface.modiication.
using. either. poly-d,l-lactide. (PDLLA),. poly-d,l-lactide-co-glycoside. (PLGA),. polyethylene.
glycol. (PEG),. special. peptide,. antibodies. or. even. combinations. of. them. seem. to. offer.
possibilities. for. drug. delivery. to. the. brain.. It. seems. that. the. mechanism. of. nanoparticle.
transportation. is. receptor-mediated. endocytosis. in. brain. endothelial. cells. and. the.
modiication.of.the.nanoparticle.surface.enables.the.adsorption.of.speciic.plasma.proteins.