Biomedical Engineering Reference
In-Depth Information
adhesions. on. the. nanoarray.. Even. when. the. dots. were. reduced. to. several. hundreds. of.
nanometers,.proteins.still.adhered.quite.preferentially.to.the.nanopattern.(Lee.et.al..2002).
The.feasibility.of.isolating.individual.biological.cells.adds.to.the.attractiveness.of.high.
resolution.fabrication.techniques,.such.as.DPN..Vega.et.al..generated.nanopatterns.using.
MHA,.in.which.the.carboxyl.groups.were.coordinated.to.zinc.ions.to.help.facilitate.tobacco.
mosaic. virus. (TMV). adhesion. to. the. surface.. An. area. of. 350.×.110.nm
2
. rectangular. fea-
tures.with.1.μm.spacing.produced.the.best.outcomes;.an.individual.TMV.resided.on.each.
nanofeature.and.was.perpendicularly.positioned.to.adjacent.TMVs.(Vega.et.al..2005).
With. signiicant. variability. in. substrate. generation,. careful. characterization. of. the.
samples. becomes. important.. Additionally,. limited. use. of. biochemical. reagents. and.
external. factors. is. highly. preferable.. The. Hunt. group. created. uniform. nanopatterned.
gold. surfaces. with. 70.nm. dots. functionalized. carboxyl,. amino,. methyl,. or. hydroxyl.
ends.positioned.equidistantly.from.each.other.(spacing:.140-1000.nm)..Culture.of.MSCs.
on. these. varied. substrates. elucidated. a. connection. between. chemical. alterations. and.
their. differing. effects. on. focal. adhesions.. Controlling. initial. cellular. interactions. via.
nanopattern. spacing. and. surface. molecules. may. also. have. later. implications,. such. as.
dictating.cell.fate.(Curran.et.al..2010).
The. behavior. of. two. pathogenic. bacteria. strains.
Escherichia coli
. K12. and.
Pseudomonas
aeruginosa
.observed.on.MHA/poly-l-lysine.(PLL).nanoarrays.once.again.implied.that.cell.
adhesion. was. governed,. in. part,. by. nanopattern. shape. and. size.. Notably,.
P. aeruginosa
.
oriented.itself.with.high.eficiency.to.DPN.patterns.consisting.of.eight.lines.and.100.nm.
spacings,. and. this. substrate. attachment. was. attributed. to. electrostatic. interactions.
between. oppositely. charged. surfaces. of. bacteria. and. PLL. (Nyamjav. et. al.. 2010).. Perhaps.
detection.systems.that.exploit.the.capability.of.modulating.pathogenic.bacterial.response.
will.become.realized.in.the.near.future.
8.2.2.2 Colloidal Lithography
Colloidal. lithography. (CL). uses. etch. masks. comprised. of. mono-dispersed. nanocolloids.
that.self-assemble.via.electrostatic.forces.on.a.surface.to.be.patterned.(Norman.and.Desai.
2006)..Formation.of.nanoscale.features.occurs.when.the.particles.or.the.areas.encompassing.
it.are.etched..This.process.generally.entails.one.of.the.following.two.approaches..Direct.
application. of. an. ion. beam. produces. pillared. structures,. while. ilm. evaporation. and.
subsequent.colloidal.particle.extraction.leaves.behind.nanopits.(Figure.8.3b;.Wood.et.al..
2002;.Hanarp.et.al..2003)..Surface.patterns.vary.with.the.type.of.colloids.used,.while.their.
spacing. depends. on. the. colloid. solution's. salt. concentration. (Norman. and. Desai. 2006)..
Among. its. advantages,. CL. enables. control. over. nanofeature. characteristics. (chemical.
composition,.size,.shape).in.both.a.cost-effective.and.eficient.manner.(Denis.et.al..2004)..
However,.the.method.tends.to.generate.little.diversity.in.shape,.due.to.the.structural.nature.
of. the. colloidal. particles. used.. Hence,. efforts. have. been. expended. to. broaden. the. shape.
repertoire.of.nanopatterns.via.modiications.to.colloidal.crystal.structure.(Choi.et.al..2010)..
Two. review. articles. provide. a. more. detailed. look. into. CL. and. its. relevant. applications.
(Yang.et.al..2006;.Wood.2007).
Dalby.et.al..etched.160.nm-high.nanocolumns.onto.a.polymethylmethacrylate.(PMMA).
substrate.. Human. ibroblasts. cultured. on. these. modiied. surfaces. experienced. a.
slower. adhesion. rate,. less. spreading,. and. lower. viability. than. on. lat. PMMA. controls..
Additionally,. these. cells. possessed. a. more. diffuse. cytoskeletal. structure—cited. as.
a. possible. consequence. of. reduced. focal. adhesion. formation. (Dalby. et. al.. 2004b).. A.
follow-up.study.using.the.aforementioned.substrates.indicated.that.ibroblast-presented.
