Biomedical Engineering Reference
In-Depth Information
technology—approximately.5-10.nm.(Schvartzman.et.al..2009)..The.fabrication.of.nano-
protrusions. has. been. achieved. using. methods. such. as. colloidal. lithography. (Hanarp.
et.al..1999),.polymer.phase.separation.(Affrosman.et.al..1996),.anodization.(Sjostrom.et.al..
2009),.and.EBL.(Wilkinson.2004)..Of.these,.the.three.former.methods.provide.a.relatively.
rapid.technique.for.fabricating.random.or.semi-random.nanoprotrusions,.whereas.EBL.
can.be.employed.to.fabricate.highly.reproducible.and.regular.nanopatterns.
A. common. theme. of. cellular. adhesion. on. nanoscale. protrusions. is. the. observation. of.
a. decrease. in. cellular. adhesion. with. increasing. nanoprotrusion. height. (Sjostrom. et. al..
2009)..Studies.thus.far.indicate.the.restrictive.nature.of.nanofeatures.measuring.>34.nm.in.
height,.whereon.focal.adhesion.formation.is.perturbed.(Table.20.1).
Recent.studies.point.to.a.reduction.in.focal.adhesion.size.(Lim.et.al..2005a,b;.Milner.and.
Siedlecki.2007).on.these.nanoprotrusion.substrates.and.that.the.changes.in.focal.adhesion.
density.stem.from.the.innate.ability.of.surface.protrusions.>34.nm.in.height.to.inhibit.pro-
tein.reinforcement.at.the.focal.adhesion.site.(Lee.et.al..2009).
Recently.studies.assessing.cellular.adhesion.on.95.nm.high.protrusions.have.demon-
strated.that.ibroblast.adhesion.is.reduced.on.features.of.this.size.(Dalby.et.al..2003a;.
TABLe 20.1
Inluence.of.Nanoscale.Protrusions.on.Cellular.Adhesion
Adhesion
Modulation
Reference
Cell Type
Chemistry
Pitch
Diameter
Height
Milner.and.
Siedlecki.
(2007)
Human.foreskin.
ibroblast
Poly(l-lactic.acid)
590.nm
500-550.nm
250-300.nm
Increased.FA.
formation
Pan.et.al..
(2012)
Rat.embryonic.
cardiomyoblast
Tantalum.oxide
110.nm
100.nm
100.nm
Reduced.FA.
formation
Dalby.et.al..
(2003a)
h-TERT.
ibroblast.cells
Poly(styrene)
1.67.±.
0.66.μm
0.99.±.
0.69.μm
95.nm
Reduced.cell.
adhesion
Berry.et.al..
(2006)
Human.bone.
marrow.
stromal.cells
Poly(styrene)/
poly(n-butyl.
methacrylate).
blend
—
0.99.±.
0.69.μm
90.nm
Reduced.FA.
formation
Lim.et.al..
(2005a,b)
Human.fetal.
osteoblastic.
cells
Poly(lactic.acid)/
poly(styrene).
blend
—
—
15-45.nm
Increased.FA.
formation
Sjostrom.
et.al..(2009)
Human.
mesenchymal.
stem.cells
Ti
40.nm
28.nm
15.nm
Increased.FA.
formation
Dalby.et.al..
(2002d)
h-TERT.
ibroblast.cells
Poly(styrene)/
poly(bromo.
styrene).blend
527.nm
263.nm
13.nm
Increased.FA.
formation
Lim.et.al..
(2005a,b)
Human.fetal.
osteoblastic.
cells
Poly(styrene)/
poly(bromo.
styrene).blend
527.nm
263.nm
11.nm
Increased.FA.
formation
Sjostrom.
et.al..(2009)
Human.
mesenchymal.
stem.cells
Ti
40.nm
28.nm
15.nm
Increased.FA.
formation
Cellular.adhesion.is.decreased.on.protrusion.structures.measuring.>34.nm.in.height.or.when.the.feature.diameter.
is.<73.nm..Conversely,.studies.show.an.increase.in.focal.adhesion.formation.when.cells.are.cultured.on.nanofea-
tures.with.a.height.<34.nm.and.a.feature.diameter.>73.nm.
