Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
Figure 20.6
(See companion CD for color igure.)
. Inluence. of. nanoscale. pits. on. focal. adhesion. formation. and.
re-enforcement..(a).Integrin.clustering.and.focal.adhesion.re-enforcement.are.unaffected.on.nanoscale.pits.
with.a.diameter.of.<73.nm.irrespective.of.pit.depth..(b).Increasing.the.pit.diameter.to.>73.perturbs.integrin.
clustering. when. the. z-dimension. of. the. pits. exceeds. approximately. 34.nm.. (c). Conversely,. focal. adhesion.
reinforcement. is. not. affected. by. nanoscale. pits. with. an. x-y. dimension. >73. provided. that. the. pit. depth. is.
<34.nm..(d).Integrin.clustering.and.cellular.adhesion.are.greatly.perturbed.on.nanoscale.pits.with.a.feature.
diameter.>73.nm.and.an.interpit.separation.of.<73.nm.
experimentally.that.a.central.tube.lumen.of.<30.nm.with.a.maximum.at.15.nm.provided.
an.effective.length.scale.for.accelerated.integrin.clustering.and.focal.adhesion.formation.
and.that.this.length.scale.strongly.enhanced.cellular.activities.in.mesenchymal.stem.cells.
(MSCs).compared.with.smooth.TiO
2
.surfaces..Conversely,.increasing.the.size.of.the.inner.
diameter. to. >73.nm. in. these. vertically. aligned. nanorods. signiicantly. reduced. cellular.
adhesion.(Park.et.al..2007)..For.a.schematic.explanation.see.Figure.20.6.
20.7 Effects of Nanoscale Grooves on Cell Adhesion
Nanogrooved. topographies. consisting. of. alternating. grooves. and. ridge. features. differ.
from.both.nanoprotrusions.and.nanopits.in.that.they.produce.very.predictable.effects.on.
cellular.morphology—which,.it.can.be.argued,.are.directly.related.to.cellular.alignment.
through.contact.guidance.(Zhu.et.al..2004)..Common.methods.of.nanogroove.fabrication.
include.EBL.(Diehl.et.al..2005),.photolithography.(Dalby.et.al..2006b),.and.direct.laser.irra-
diation.(Zhu.et.al..2005),.which.may.be.employed.to.yield.anisotropic.substrates.with.vary-
ing.feature.widths.and.depths.(Table.20.3).
A. key. fabrication. tenet. of. nanogroove. substrates. for. the. study. of. cell-interface. inter-
actions. is. that. of. biomimetic. ECM. design,. an. attempt. to. mimic. the. topographical. cues.
imparted. by. the. ibrous. components. found. in. the. ECM,. including. individual. ibril.
