Biomedical Engineering Reference
In-Depth Information
Collagen.ibrils.are.capable.of.extending.up.to.tens.of.micrometers.in.length.and.have.a.
diameter.between.260.and.410.nm..Nanofabricated.APS.substrates.have.been.created.with.
pillar.geometries.in.this.size.scale..Primary.hepatocytes.were.cultivated.on.the.substrate,.
and.showed.enhanced.cell.attachment.and.spreading,.and.most.importantly,.maintained.
metabolic.function.
Another.important.factor.for.successful.in.vivo.applications.is.to.pattern.special.geom-
etries. between. the. polarized. tissues. that. orients. endothelial. cell. assembly. to. lumens..
A.different.approach.to.providing.hepatocytes.with.an.ECM-like.microenvironment.is.by.
culturing. them. on. nanoibrous. galactosylated. chitosan. scaffolds.. The. embedded. galac-
tose.ligands.enable.the.formation.of.lat.aggregates.by.promoting.interaction.between.the.
ligands.and.the.nanoscale.surface.receptors.on.hepatocytes,.and.showed.a.higher.level.of.
liver.function.(Feng.et.al..2009).
22.3.3 Biomimetic Scaffolds with Nanoscale Surface Modification
As. more. understanding. is. gained. on. how. nanoscale. surfaces. are. synthesized. and. how.
they.inluence.cell.responses,.more.of.these.techniques.and.knowledge.are.put.to.direct.
application. in. cutting-edge. tissue. engineering. work.. As. mentioned. in. the. previous. sec-
tion,. liver. regeneration. has. been. a. very. important. area. of. interest,. and. nanotechnologic.
approaches.have.been.applied.to.the.liver..Nanotechnology.has.also.shown.great.potential.
in.neural.tissue.engineering,.cardiovascular.tissue.regeneration,.retina.regeneration,.and.
even.medical.adhesives.
Nanotechnology.had.been.proven.very.useful.in.research.on.the.complex.nervous.sys-
tem.as.its.contact.guidance.phenomenon.and.the.topographical.cues.generated.enable.the.
in. vitro. regeneration. of. highly. sophisticated. and. densely. packed. neural. cells. (Bettinger.
et.al..2009b)..Silk.ibers.had.shown.enhancement.of.Schwann.cell.regeneration.by.promot-
ing. cell. growth. (Yang. et. al.. 2007a,b).. The. high. degree. of. alignment. of. conducting. ibers.
created.by.electrospinning.has.enabled.the.studies.in.neural.conductivity.and.regenera-
tion.(Li.et.al..2006).
Nanotechnology.had.also.been.applied.in.cardiovascular.tissue.engineering.to.accom-
modate. the. complex. properties. and. features. of. myocardium. and. valvular. tissues.. The.
complexity. of. vasculature. surrounding. the. heart. tissue. had. presented. particularly. chal-
lenging.to.engineers,.as.the.system.requires.maintenance.of.mechanical.strength.needed.
to.withstand.high.pressure.and.the.pulsatile.environment..Nanotechnology.is.capable.of.
signaling.cells.to.control.cell.adhesion,.movement,.and.morphology.and.therefore.become.
a.promising.tool.for.the.engineering.of.myocardial.tissue,.heart.valve.implants,.and.com-
plex.vessel.graft.development.(Choudhary.et.al..2007,.Wan.et.al..2010).
In.Neeley.et.al..(2008),.ultrathin.PGS.scaffolds.were.fabricated.with.micropatterns.to.pro-
mote.retinal.progenitor.cells.(RPCs).regeneration.by.replacing.photoreceptors,.which.has.
been.considered.a.promising.therapy.for.the.treatment.of.retinal.degeneration..The.micro-
fabricated.PGS.scaffold.showed.strong.RPCs.adhesion.and.exhibited.excellent.mechani-
cal. properties. for. delivering. RPCs. to. the. subretinal. space.. Cells. grown. on. the. scaffold.
for.7.days.expressed.a.mixture.of.immature.and.mature.markers,.suggesting.a.tendency.
toward.differentiation..As.nanoscale.features.are.known.to.guide.cell.growth,.it.is.consid-
ered.the.next.step.for.the.alignment.of.retinal.cells.
Nanoscale.features.are.used.not.only.in.direct.tissue.applications,.but.also.act.as.med-
ical. biodegradable. polymer. adhesives. capable. of. adapting. to. or. recovering. from. vari-
ous.mechanical.deformations.while.retaining.strong.attachment.to.tissues..In.Mahdavi.
et.al..(2008),.a.polymer.stemming.from.PGS,.poly(glycerol-co-sebacate.acrylate).(PGSA),.
