Biomedical Engineering Reference
In-Depth Information
can.collect.true.3D.topographical.information.and.measure.surface.mechanical.proper-
ties.at.nanometer-.and.piconewton.(pN)-scale.resolution..Thus,.AFM.enables.the.inves-
tigation.of.fresh.and.air-dried.erythrocytes.without.the.need.for.any.other.treatments,.
such.as.ixation.and.surface.coating,.that.may.alter.delicate.nanostructures.on.the.sur-
face.of.IRBCs..In.the.late.1990s.Aikawa.was.the.irst.to.use.AFM.to.study.malaria.IRBCs.
9
.
Despite.some.early.challenges.(such.as.artifactual.AFM.images.showing.double-headed.
knobs),.an.optimized.protocol.now.exists.to.allow.accurate.and.repeatable.AFM.imag-
ing.of.IRBCs.
10
One. of. the. key. advantages. of. AFM. for. the. examination. of. malaria. IRBCs. is. that. the.
same.sample.can.be.examined.separately.or.simultaneously.by.other.imaging.methods,.
especially.optical.imaging.methods..For.example,.an.individual.IRBC.can.be.located.using.
an.indexed.copper.grid.on.the.underside.of.the.slide..The.targeted.cell.is.initially.scanned.
using.the.AFM;.subsequently,.the.same.cell.can.be.ixed.for.an.indirect.luorescent.assay.
(luorescently.linked.antibodies.binding.to.a.protein.of.interest),.and.inally,.the.cell.can.
be.stained.with.a.standard.Giemsa.malaria.stain.to.accurately.stage.the.cell.under.inves-
tigation.(Figure 15.2)..Infected.erythrocytes. splutter.coated.for.SEM.examination.cannot.
be.stained.afterward,.and.it.is.almost.impossible.to.determine.the.erythrocytic.stage.of.a.
parasite,.or.even.if.a.cell.is.really.infected..Table 15.1.outlines.the.major.advantages.and.
disadvantages.of.AFM.in.comparison.with.SEM.and.TEM.
Ring
Early Trophozoite
Mid Trophozoite
Late Trophozoite
Schizonts
Bursting Schizonts
FIGURE 15.2
(See. color. insert.). Corresponding. AFM. imaging. of. external. surface. and. Giemsa. staining. of. interior. parasite.
structure.of.lab-cultured.
P. falciparum
.IRBCs..(Details.shown.in.Li,.A.,.et.al.,.
J. Microbiol.
.
Methods
,.66,.434-439,.
2006.)
