Biomedical Engineering Reference
In-Depth Information
scaffolds. in. vitro.. In. addition,. the. coaxial. electrospun. scaffolds. could. reduce. virus. dis-
semination.and.its.corresponding.inlammatory.cytokine.secretion.
Although. viral. carriers. primarily. eficiently. infect. cells. and. prolong. gene. expression,.
they. are. associated. with. important. drawbacks.. They. can. potentially. cause. undesirable.
consequences,.such.as.toxicity,.uncontrolled.proliferation.of.modiied.cells,.inlammation,.
immunological.reactions,.and.oncogenicity.
103,104
.These.concerns.have.limited.the.viral.car-
rier.application.in.clinical.use..Nonviral.vectors.have.been.of.great.interest.because.they.
have.been.determined.as.a.clinically.safer.alternative.due.to.the.lack.of.those.viral.limita-
tions..Many.biomaterials.have.been.developed.to.create.synthetic.gene.delivery.vectors..
The.majority.of.the.biomaterials.are.cationic.polymers,.cationic.lipids,.liposomes,.chitosans,.
inorganic.nanoparticles,.and.dendrimers.
99,105-108
.The.use.of.eletrospinning.associated.with.
these.gene.carriers.to.deliver.a.genetic.portion.to.the.target.cell.has.been.studied..Nie.and.
Wang
99
.studied.the.delivery.of.bone.morphogenetic.protein-2.plasmid.DNA.into.human.
marrow.stem.cells.(hMSCs).in.vitro.using.electrospun.poly(lactide-co-glycolide).(PLGA)/
hydroxyapatite.(HAp).composite.scaffolds..They.loaded.the.plasmids.into.the.ibrous.scaf-
folds. in. three. different. ways:. coated. naked. DNA. onto. the. ibers,. coated. DNA/chitosan.
nanoparticles.onto.the.ibers,.and.encapsulated.DNA/chitosan.nanoparticles.into.scaffold.
by.mixing.with.PLGA/HAP.solution.prior.to.electrospinning..In.vitro
studies.show.that.
the. electrospun. scaffolds. could. release. the. plasmids. or. plasmid/chitosan. nanoparticles,.
and.the.sustained.release.could.be.up.to.45-55.days..The.amount.of.HAp.loaded.in.the.
scaffold.also.affected.the.release.rate..Moreover,.the.released.DNA.retained.its.structural.
and.biological.properties,.even.after.60.days.of.releasing..High.transfection.eficiency.could.
be.sustained.with.the.aid.of.a.chitosan.carrier,.especially.in.the.latter.way.of.loading.the.
plasmids.into.the.scaffold..In.2009,.Nie.et.al.
109
.also.investigated.the.release.of.BMP-2.plas-
mid.from.the.previously.studied.scaffolds.in.vivo
using.nude.mice.as.an.animal.model..
Animal.experiments.showed.that.the.bioactivity.of.the.BMP-2.plasmid.released.from.the.
scaffolds. was. maintained. and. could. improve. new. bone. formation. and. healing. of. bone.
defects.of.mice.tebia.in.vivo..The.scaffolds.containing.DNA/chitosan.nanoparticles.trans-
fected.cells.more.eficiently.than.naked.DNA..The.in.vivo
test.results.in.bone.healing.were.
well.correlated.with.the.in.vitro.release.proiles.of.plasmid.in.their.previous.work.
23.4 Conclusions
The.application.of.electrospinning.to.therapeutic.molecule.delivery.holds.great.promise..
Selection.of.appropriate.polymers.for.speciic.therapeutics.allows.for.controlled.drug.or.
bioactive.molecule.release.rate.and.behavior.
References
.
1.. A..Formhals,.Process.and.apparatus.for.preparing.artiicial.threads,.U.S..Patent.(1934).1975504.
.
2.. M..Jacobsen,.
Chemiefasern/Textilind
.(1991).36-41.
.
3.. P.X..Ma,.R..Zhang,.Synthetic.nano-scale.ibrous.extracellular.matrix,.
J. Biomed. Mater. Res. A
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(1999).60-72.
