Biomedical Engineering Reference
In-Depth Information
use.require.a.high.concentration.of.pathogen.cells,.typically.from.1.million.to.10.million.
cells.per.milliliter.of.luid..The.tests.also.rely.on.a.process.known.as.enrichment,.which.
occurs.when.a.sample.believed.to.be.contaminated.grows.for.a.period.of.time.in.a.nutrient.
broth.to.allow.any.pathogen.cells.present.to.multiply..Other.tests.rely.on.DNA.markers,.
but.these.also.can.take.days.to.process,.which.is.a.problem.because.by.the.time.test.results.
come.back,.food.products.may.already.be.in.food.supply.warehouses.or.on.store.shelves.
Nanosized.iron.oxides,.especially.Fe
2
O
3
.and.Fe
3
O
4
,
.
have.been.of.intense.interest.due.to.
their.characteristic.features,.such.as.electric,.optical,.magnetic,.and.photosensitive.proper-
ties..In.addition.to.their.inherent.characteristics,.their.amenability.for.surface.modiication.
has.led.to.a.great.extension.of.their.utilization.in.biological,.medical,.and.environmental.
applications..Despite.intense.efforts.in.the.study.of.magnetic.nanoparticles,.their.applica-
tions.in.biomedicine.and.the.environment.are.just.emerging.
In.the.current.study,.we.present.a.simple.sodium.chloride-assisted.method.to.prepare.
multiple-element.magnetic.nanoparticles.(MMNs).and.use.of.those.MMNs.for.fast.detec-
tion.and.removal.of.bacterial.pathogens.from.water.resources.
17.2 MaterialsandMethods
17.2.1 Preparation of Multiple-Element Magnetic Nanoparticles (MMNs)
Fly.ash.collected.from.chimneys.of.iron.and.steel.factories.was.used.for.the.production.of.
multiple-element.magnetic.nanoparticles.(MMNs).
Wet.sieving.of.ly.ash.through.a.25.µm.sieve.was.performed,.and.then.dried.in.an.oven.
(temperature.of.100-110°C.for.55.min)..Magnetites.in.the.dry.product.were.separated.by.a.
magnetic.ield.(3.8.×.10
4
.G)..These.constituted.95%.of.the.original.product.
The.dried.magnetic.product.was.then.well.mixed.with.sodium.chloride.salt.(NaCl).(ratio:.
1:10).in.a.thin,.semispherical.ceramic.pot.and.stirred.thoroughly.with.a.teaspoon.to.pro-
vide.for.good.dispersion..The.contents.of.the.pot.were.emptied.into.another,.similar.pot..
The.magnetites.in.the.ash.attached.to.the.inner.surface.of.the.original.pot.were.harvested.
by.applying.a.permanent.magnet.of.3,000.G.at.the.outer.surface.of.the.pot,.and.attached.
dust.was.blown.away.by.jet.air.using.a.small.air.pump.
The.magnet.was.removed.and.magnetites.were.collected.in.a.test.tube.(50.ml.capacity)..
This. process. was. repeated. several. times. until. the. required. sample. size. of. magnetites.
was.produced.
The.test.tube.was.illed.with.double-distilled. water.(50.ml).and.vortexed.for.5.min.to.
provide.for.good.dispersion.of.the.magnetites.in.the.solution..The.tube.with.the.content.
was.centrifuged.for.20.min.at.3,400.rpm,.and.the.supernatant.(~30.ml).of.the.water.fraction.
was.poured.into.another.test.tube.
Characterization.of.the.MMN.in.terms.of.sizes.and.of.chemical.components.was.con-
ducted.using.transmission.electron.microscope.(Fig..1),.scanning.electron.microscope.and.
atomic.absorption.
17.2.2 Characterization of the MMNs Using Atomic Absorption
MMNs.were.dissolved.in.30.ml.of.35%.HCL.and.were.subjected.to.mineral.analysis.using.
atomic.absorption.
