Biomedical Engineering Reference
In-Depth Information
the. researchers. to. clearly. differentiate. the. toxic. effects.of. metal. oxide. nanoparticles. and.
solubilized. metal. ions.. It. was. shown. that. metal. oxide. nanoparticles. do. not. necessarily.
have.to.enter.the.cells.to.cause.toxicity..Rather,.it.seems.to.be.the.intimate.contact.between.
the.bacterial.cell.wall.and.the.particles..This.may.cause.changes.in.the.microenvironment.
in. the. vicinity. of. the. organism-particle. contact. area,. and. either. increase. the. solubiliza-
tion. of. metals. or. generate. extracellular. reactive. oxygen. species. (ROS). that. may. damage.
cell.membranes..Their.results.on.nano-.and.bulk.metal.oxides.are.in.agreement.with.the.
SCENIHR. Report. (2007), 65 . which. states:. “Not. all. nanoparticle. formulations. have. been.
found.to.induce.a.more.pronounced.toxicity.than.the.bulk.formulations.of.the.same.sub-
stance.”.This.suggests.that.the.evaluation.of.nanoparticle.formulations.should.be.carried.
out.on.a.case-by-case.basis.
The.toxicities.of.nanoscaled.aluminium,.silicon,.titanium,.and.zinc.oxides.to.bacteria.( B.
subtilis, E. coli ,.and. P. luorescens ).were.examined.and.compared.to.those.of.their.respective.
bulk.counterparts. 66 .All.nanoparticles.except.TiO 2 .exhibited.signs.of.toxicity.to.the.tested.
bacteria,.compared.to.the.control..The.toxicity.of.nanoparticles.was.not.only.from.the.dis-
solved.metal.ions,.but.also.from.their.greater.tendency.to.attach.to.the.cell.walls.than.to.
aggregate. together.. The. sensitivity. of. bacteria. to. each. type. of. nanoparticles. varied. with.
the.species..The.ZnO.nanoparticles.were.the.most.toxic.of.the.nanoparticles.studied..The.
effect.of.natural.environmental.parameters.on.nanoparticle.toxicity.and.the.exact.toxicity.
mechanism.need.to.be.studied.thoroughly.
A.thorough.review.on.in.vitro.assessments'.nanomaterial.toxicity.was.reported.by.Jones.
and.Grainger. 67 .The.review.discussed.current.methodologies.used.to.assess.nanomaterial.
physicochemical. properties. and. their. in. vivo. effects.. Therefore,. physicochemical. nano-
material.assays.need.to.be.improved.to.provide.accurate.exposure.risk.assessments.and.
genuine.predictions.of.in.vitro.behavior.and.therapeutic.value.
18.7 Conclusions
This. chapter. elaborates. on. the. use. of. nanomaterials,. particularly. metal. oxide. nanopar-
ticles,. polymer. composites,. and. dyes. in. the. textile. industry,. especially. as. antimicrobial.
agents..Metal.oxide.nanoparticles.consist.of.silver,.titanium.dioxide,.zinc.oxide,.magnesium.
oxide,.calcium.oxide,.copper.oxide,.and.cerium.oxide.nanoparticles..Silver.nanoparticles.
are.considered.an.effective.agent.against.microorganisms..Titanium.dioxide.nanoparticles.
require.activation.by.UV.light.and.are.less.attractive.than.zinc.oxide.nanoparticles.in.the.
sense. that. the. latter. still. have. antimicrobial. activity. even. in. the. dark.. Considering. the.
production.cost,.nano-zinc.oxide.is.the.most.effective..Therefore,.the.future.trend.of.using.
nano-zinc.oxide.in.the.textile.industry.is.imminent.
Chitosan,. chitosan. derivatives,. and. henna. dyes. are. utilized. as. natural. antimicrobial.
agents.in.the.textile.industry..Since.most.antibacterial.agents.are.toxic.chemicals,.an.ideal.
textile.antimicrobial.should.be.safe.and.environmentally.friendly.or.benign,.in.addition.to.
the.killing.of.unintentional.microorganisms..Thus,.natural.antimicrobial.agents.would.be.
better.suited.for.these.purposes.
Methods.for.stabilizing.nanoparticles.on.textile.surfaces,.mechanisms.of.action.of.nano-
materials,.and.their.toxicities.were.also.mentioned.
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