Biomedical Engineering Reference
In-Depth Information
Ti
d= 30 nm
50 nm
70 nm
100 nm
100 µm
(a)
Planar
300 nm
500 nm
1 µm
20 µm
(b)
Figure 8.5
(See companion CD for color igure.)
.Size.variations.in.topographical.features.cause.cells.to.respond.differently..
(a).Following.a.24.h.culture.period,.hMSCs.seeded.on.a.lat.surface.and.on.TiO
2
.nanotubes.reveal.morphological.
differences..An.increase.in.nanotube.diameter.correlated.to.greater.cell.elongation..(Reprinted.with.permission.
from.Oh,.S..et.al.,.
Proc. Natl. Acad. Sci. USA
,.106(7),.2130,.2009.).The.red.arrows.highlight.signiicant.cell.elongation,.
while.the.yellow.arrows.note.the.presence.of.lamellopodia,.implying.enhanced.hMSC.mobility..(b).Macrophages.
were.seeded.onto.PDMS.substrates:.a.lat.control.and.ones.of.different.nanograting.sizes..After.48.h,.changes.in.
morphology,.spreading,.and.elongation.were.evident..(Reprinted.from.
Biomaterials
,.31(13),.Chen,.S.,.J..A..Jones,.Y..
Xu.et.al.,.Characterization.of.topographical.effects.on.macrophage.behavior.in.a.foreign.body.response.model,.
3479-3491,.Copyright.2010,.with.permission.from.Elsevier.).These.manifested.most.prominently.in.the.500.nm.
and.1.μm.nanogratings..However,.the.mechanism.responsible.for.this.behavior.remains.unclear.at.this.point.
proliferation.. Distinct. morphological. differences. were. also. seen. between. ibroblasts. on.
patterned. and. smooth. substrates,. with. the. former. adopting. a. more. elongated. shape..
Focal.adhesions.located.on.nanopillar.surfaces.also.seemed.thinner.and.less.structurally.
organized. (Milner. and. Siedlecki. 2007).. Human. MSCs. cultured. on. titanium. surfaces.
responded. differently. to. various. nanopillar. heights. (15,. 55,. 100.nm),. with. the. shortest.
proving.most.conducive.to.focal.adhesion.formation..Likewise,.expression.of.bone.lineage.
markers.osteocalcin.and.osteopontin.appeared.most.prominently.for.15.nm.nanopillars.
and.decline.markedly.when.height.was.elevated.(Sjöström.et.al..2009)..A.more.recent.study.
by. the. aforementioned. group. also. demonstrated. similar. cellular. responses. by. human.
MG-63.osteoblasts.(Sjöström.et.al..2011)..Rat.embryonic.cortical.neurons.were.transferred.
to. electrodes. nanopatterned. with. pillars.. These. nanofeatures. effectively. hindered. cell.
migration,. but. did. not. impede. cell. growth.. This. endeavor. sought. to. maintain. neuron.
functionality,.while.keeping.them.in.place.for.accurate.tracking.and.recording.of.individual.
neurons. (Xie. et. al.. 2010).. Nanopillar. (20.nm. diameter,. 2.5.μm. height). silicon. substrates,.
made.hydrophobic.with.a.gold.coating,.yielded.greater.adhesion.and.proliferation.of.rat.
MSCs. compared. to. micropillar. (2.μm. diameter,. 2.5.μm. height). and. planar. counterparts..
A. decrease. in. cell. spreading. and. cytoskeletal. organization. resulted. exclusively. in. the.
presence. of. the. nanopillars.. Cell. clusters. predisposed. to. an. osteogenic. fate. were. also.
observed. to. be. a. consequence. of. nanotopography. modulation.. This. work. highlighted.
