Biomedical Engineering Reference
In-Depth Information
A
B
C
D
FIGURE 10.1
SEM.micrographs.of.(A).unseeded.and.(B).Saos-2.cell-seeded.PHBV-P(L,DL-LA).(70:30).scaffolds.14.days.after.
incubation..(C).CLSM.images.of.Saos-2-seeded.PHBV10.scaffolds.7.days.after.incubation.(top.view.showing.cell-
matrix.interaction)..(D).CLSM.of.cell.iniltration.within.the.scaffold.as.viewed.in.cross.section.(Z-axis.direction)..
(From.Ndreu.et.al.,.
Nanomed
,.3,.45-60,.2008.)
occurring.enzymes,.and.therefore,.they.can.be.used.as.biodegradable.scaffolds..The.most.
commonly. used. natural. polymers. are. proteins. (collagen,. gelatin,. ibrinogen,. silk,. casein,.
etc.).and.polysaccharides.(chitosan,.cellulose,.hyaluronic.acid,.etc.)..Sangsanoh.et.al..(2009).
studied. biological. evaluation. of. electrospun. chitosan. nanoibers. and. ilms. in. vitro
with.
four.different.cell.types:.Schwann.cells,.osteoblast-like.cells,.keratinocytes,.and.ibroblasts..
Both.substrate.forms.were.seen.to.support.cell.attachment.and.especially.promoted.pro-
liferation.of.keratinocytes..While.Schwann.cells.attached.well.on.nanoibrous.structures,.
they.did.not.adhere.on.ilms..On.the.other.hand,.even.though.osteoblast-like.cells.and.ibro-
blasts.showed.good.attachment.on.both.nanoibrous.and.ilm.surfaces.they.did.not.prolifer-
ate.well.(Sangsanoh.et.al.,.2009)..Jin.et.al..(2004).produced.silk.ibroin/poly(ethylene.oxide).
(PEO).nanoibrous.matrices.(700-750.nm),.examined.the.behavior.of.human.bone.marrow.
stromal. cells. (BMSCs),. and. reported. that. the. matrices. supported. BMSC. attachment. and.
proliferation.during.14.days.of.incubation.with.extensive.matrix.coverage.(Jin.et.al.,.2004).
A. blend. of. natural. and. synthetic. polymers. is. advantageous. in. that. they. combine. the.
better. mechanical. properties. of. synthetic. polymers. with. the. biofunctionality. of. natural.
ones.. In. this. approach. the. properties. of. the. scaffold. can. be. changed. easily. and. can. be.
arranged.as.desired.by.changing.the.composition.and.the.ratio.of.the.blend..Ngiam.et.al..
(2009).prepared.nano-hydroxyapatite.(n-HAp).containing.electrospun.PLGA.and.PLGA/
collagen.(COL).blend.nanoibers..Biomineralization.of.n-HAp.on.electrospun.nanoibers.
was. achieved. by. using. an. alternate. calcium. and. phosphate. solution. dipping. method..
n-HAp.crystallite.deposition.was.predominant.on.PLGA/COL.nanoibers.compared.to.on.
PLGA,.which.shows.that.collagen.is.a.good.template.for.n-HAp.nucleation..It.was.shown.
that.the.amount.of.n-HAp.present.had.a.greater.inluence.on.early.cell.behavior,.such.as.
attachment.and.proliferation,.than.in.the.intermediate.stages.because.their.ALP.and.total.
protein.expression.results.for.mineralized.PLGA.and.PLGA/COL.were.comparable.dur-
ing.the.culture.period.(Ngiam.et.al.,.2009).
An. important. requirement. in. bone. tissue. engineering. is. that. the. scaffold. should. be.
highly.porous.so.that.cells.can.be.homogeneously.distributed.throughout.the.structure..
Poor. cell. iniltration. into. the. structure. is. reported. when. electrospun. scaffolds. are. used;.
the.cells.are.observed.more.on.the.surface.than.the.inside.of.the.scaffold..Therefore,.it.is.
of.great.importance.to.ind.an.approach.to.produce.nanoibrous.scaffolds.with.a.higher.
degree.of.cell.penetration..Ekaputra.et.al..(2008).used.three.strategies.to.solve.this.problem:.
selective.leaching.of.a.water-soluble.iber.phase.(PEO.or.gelatin),.the.use.of.micron-sized.
