Atomic Force Microscopy - The Nanobiotechnology - page 381

+/-

+/- Au
nanoparticles Small

molecules

Substrate

0 V 0 V

-6 V +6 V

200 nm

20 nm

(a)

2

1

0 0

40 80

500 nm

0 nm 10 nm (b) Distance (nm)

(A) (B) (C)

Figure 16.4
(See companion CD for color igure.) .AFM.serves.as.a.nanomanipulator.in.multifaceted.ways..(A).DPN.uses.
an.AFM.probe.as.a.pen.to.selectively.deposit.small.molecules.onto.a.substrate..The.images.show.patterning.of.
a. small. peptide. (middle. panel). (Reprinted. with. permission. from. Agarwal,. G.,. Sowards,. L.A.,. Naik,. R.. et. al.,.
Dip-pen.nanolithography.in.tapping.mode,. J. Am. Chem. Soc .,.125(2),.580..Copyright.2003b,.American.Chemical.
Society.). and. a. globular. protein. (bottom. panel). using. electrochemical. DPN. (Reprinted. with. permission. from.
Agarwal,.G.,.Naik,.R.R.,.Stone,.M.O.,.Immobilization.of.histidine-tagged.proteins.on.nickel.by.electrochemical.
dip. pen. nanolithography,. J. Am. Chem. Soc., . 125(24),. 7408.. Copyright. 2003a,. American. Chemical. Society.). (B).
Lifting. of. charged. gold. nanoparticles. by. applying. electric. potential. to. the.AFM. probe.. (Reprinted. from. Xu,. J.,.
Kwak,. K.,. Lee,. J.. et. al.:. Lifting. and. sorting. of. charged.Au. nanoparticles. by. electrostatic. forces. in. atomic. force.
microscopy.. Small ..2010..6(19)..2105-2108..Copyright.Wiley-VCH.Verlag.GmbH.&.Co..KGaA.).Lifting.is.depen-
dent.on.particle.size.and.the.polarity.and.magnitude.of.applied.potential..(C).In.nanografting.the.AFM.probe.
scrapes.away.a.SAM.to.expose.a.region.of.the.substrate..Another.molecule.type.that.is.suspended.in.the.solution.
surrounding. the. sample. assembles. into. the. newly. exposed. areas..AFM. height. image. and. section. proile. show.
two.nanoislands.of.C 22 S.and.C 18 S.molecules.created.with.nanografting..(Reprinted.with.permission.from.Xu,.S.,.
Miller,.S.,.Laibinis,.P.,.Fabrication.of.nanometer.scale.patterns.within.self-assembled.monolayers.by.nanografting,.
Langmuir ,.15(21),.7244..Copyright.1999,.American.Chemical.Society.)

tool.for.selectively.lifting,.sliding,.or.depositing.atoms,.molecules,.and.nanoparticles.onto.
a.desired.substrate.for.a.wide.range.of.applications.(Gilbert.and.Cavalleri.1996;.Grobelny.
et.al..2006;.Tang.et.al..2004;.Ding.2008)..Depending.on.the.application,.the.specimen.may.
require.horizontal.(X-Y).and/or.vertical.(Z).manipulation;.the.AFM.is.a.versatile.tool.that.
meets.both.of.these.needs.
Horizontal.nanomanipulation.is.generally.conducted.in.static.mode.of.AFM,.in.which.
the.particles.are.“pushed”.by.the.AFM.probe.to.its.destination..Dynamic.modes.of.AFM.