Biomedical Engineering Reference
In-Depth Information
Information. such. as. changes. in. cell. size. and. granularity. can. be. elucidated. in. this. way..
Due. to. the. overall. loss. of. size. for. apoptotic. cells. through. water. loss. and. nuclear. frag-
mentation,.apoptotic.cells.give.lower.forward.scatter.and.higher.side.scatter.values.than.
viable.and.necrotic.cells,.indicating.the.smaller.size.as.well.as.different.nucleus/cytoplasm.
consistency.
149
.The.neutral.red.assay.procedure.is.another.method.for.the.identiication.of.
surviving/viable.cells.after.treatment.with.the.materials.of.choice..The.assay.is.based.on.
the.ability.of.viable.cells.to.incorporate.and.bind.neutral.red.(3-amino-
m
-dimethylamino-
2-methyl-phenazine. hydrochloride),. a. weakly. cationic. supravital. dye. that. penetrates. the.
cell.membrane.through.a.nonionic.diffusion.process.and.then.subsequently.accumulates.
in.the.lysosomes.
150
.Changes.in.the.cell.surface.and.lysosomal.membrane.lead.to.decreased.
neutral. red. uptake. and. binding,. thus. making. it. possible. to. distinguish. between. dam-
aged.and.viable.cells.through.spectrophotometric.measurements.
151
.The.quantiication.of.
dye.extracted.from.the.treated.cells.has.been.shown.to.be.linear.with.cell.numbers,.with.
cytotoxicity.expressed.as.a.concentration-dependent.reduction.of.the.neutral.red.uptake,.
giving.a.robust,.sensitive.signal.for.both.cell.integrity.and.growth.inhibition.
152
.Staining.
techniques. have. also. been. shown. to. effectively. quantify. the. DNA. loss. as. a. function. of.
apoptosis,.for.instance,.the.use.of.intercalating.DNA.dyes.such.as.propidium.iodide.(PI).
and. 7-aminoactinomycin. D. (7-AAD).
153
. Hypotonic. solutions. of. PI. dye. have. been. shown.
to.be.among.the.easiest.and.most.rapid.methods.of.DNA.staining.for.apoptosis.measure-
ments,.strengthening.their.use.in.large-scale.in.vitro.investigations.
154
24.7 SummaryandOutlook
Noble.metal.nanoparticles.or.mixed.monolayer-protected.clusters.(MMPCs).are.attractive.
candidates.for.use.in.the.development.of.nanoparticle-based.systems.for.diagnostic.and.
therapeutic.purposes.due.to.their.ease.of.fabrication.and.native.biocompatibility..However,.
a.lot.still.needs.to.be.done.in.order.to.address.the.health,.safety,.and.environmental.issues.
of.nanomaterials.in.general..If.the.development.of.future.advanced.MMPCs.could.focus.on.
ensuring.that.these.systems.are.more.stable,.robust,.biocompatible,.and.versatile.enough.to.
be.used.in.vivo,.it.is.clear.that.the.future.therapeutic.platform.would.rely.on.noble.metal.
nanoparticles..It.must.be.emphasized.that.the.beneits.of.nanotechnology.have.been.over-
stated.in.some.respects,.and.thus.could.lead.to.overreliance.and.appearing.as.a.quick.ix.
to.some.of.the.long-standing.scientiic.challenges..Again,.if.this.is.true,.and.lives.could.be.
improved.(and.thus.extended.considerably).through.nanotechnology,.then.other.socioeco-
nomic.factors.need.to.be.factored.in.
References
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1.. Jain.K.K.,.
Drug Discov. Rev.
,.2005,.10.(21),.1435.
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2.. Brown.D..and.Supertia-Furga.G.,.
Drug Discov. Today
,.2003,.8,.1067.
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3.. Dobrovolskaa.M.A..and.McNeil.S.E.,.
Nature Nanotechnol.
,.2007,.2,.469.
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4.. Azzazy.H.M.E.,.Mansour.M.M.H.,.and.Kazmierczak.S.C.,.
Clin. Chem.
,.2006,.52(7),.1238.
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5.. Morghimi.S.M.,.Hunter.A.C.,.and.Murray.C.J.,.
FASEB J.
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6.. Pei.R.,.Yang.X.,.and.Wang.E.,.
Analyst
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