Biomedical Engineering Reference
In-Depth Information
myosin.(80.ms.per.frame).and.gliding.of.actin.ilaments.on.myosin.V.(Ando.et.al..2001),.and.
the. unidirectional. movement. of. individual. kinesin. molecules. along. microtubules. in. real.
time.(0.64.s.per.frame).(Ando.et.al..2003)..However,.it.should.be.noted.that.in.addition.to.
unique.hardware.modiications,.high-speed.AFM.also.requires.special.sample.preparation.
methodologies. for. biological. samples. mostly. due. to. the. increasingly. rapid. scanning. rate.
of.the.high-speed.AFM.probe.across.the.sample..High-speed.AFM.is,.thus,.an.upcoming.
technique.(Ando.2012).currently.conined.to.research.groups.and.is.only.available.at.this.
time.on.selective.commercial.AFM.systems.(Table.16.2).
Other. approaches. to. improve. AFM. imaging. and. related. capabilities. have. focused. on.
the.modes.of.engagement.of.the.AFM.cantilever.with.the.sample..For.example,.the.seesaw.
method.by.Torun.et.al..improves.imaging.speed.and.displacement.range.simultaneously..
This.method.involves.a.lever.and.fulcrum.“seesaw-like”.actuation.mechanism.that.uses.a.
small,.fast.piezoelectric.transducer.(Torun.et.al..2011)..Upcoming.AFM.modes.involve.the.
use.of.magnetically.actuated.cantilevers.that.are.capable.of.reducing.noise.in.luid.imag-
ing,.such.as.the.magnetic.AC.(MAC).mode.(Ge.et.al..2007).and.the.iDrive.(Ip.et.al..2010)..
More. attractive,. user-friendly. options. include. ScanAsyst. and. quantitative. imaging. (QI);.
these.are.self-optimizing.imaging.modes.that.can.provide.direct.force.control.at.each.point.
in.an.image..Unfortunately,.these.specialized.AFM.modes.are.available. only.on.limited.
commercial.AFM.systems.(see.Table.16.2),.and.their.versatility.over.the.standard.static.and.
dynamic.modes.for.various.applications.in.nanobiotechnology.are.yet.to.be.established.
16.7 Conclusions and Future Perspectives
As.described.earlier.in.this.chapter,.the.AFM.serves.as.an.indispensable.tool.for.nanobio-
technology. based. on. its. three. major. capabilities,. namely,. (1). imaging,. (2).force. measure-
ments,. and. (3). nanomanipulation,. both. in. ambient. air. and. in. luid. environments. at. the.
nanoscale. level.. Most. commercial. AFM. systems. enable. all. of. these. capabilities. and. are.
therefore.considered.multimodal.instruments..Custom-built.AFM.systems.are.generally.
targeted.to.enhance.and.improve.one.of.these.capabilities..Over.the.past.decade,.the.AFM.
has.also.been.integrated.with.other.biophysical.techniques.such.as.light.and.luorescence.
microscopy,. scanning. electron. microscopy,. and. near. ield. scanning. optical. microscopy..
The. development. of. improved. probes. for. AFM. applications. is. yet. another. area. that. has.
witnessed.rapid.growth.and.broadened.the.spectrum.of.applications.in.nanobiotechnol-
ogy..We.can,.therefore,.expect.that.the.coming.years.will.continue.to.see.a.rise.in.the.“stan-
dard”.applications.of.AFM.for.nanobiotechnology,.along.with.novel.applications.that.may.
stem.from.recent.developments.such.as.faster.scanning,.imaging.the.interior.of.samples,.
higher.resolution,.and.integrated.AFM.capabilities.
Acknowledgments
The.authors.would.like.to.acknowledge.the.Multidisciplinary.Team.Building.Grant.fund-
ing.provided.by.the.Institute.of.Materials.Research.at.The.Ohio.State.University.
