Bacterial Nanocellulose as a Structured Platform for Conductive Biopolymers 243
extrinsic.approach.has.been.receiving.increasing.attention,.as.it.allows.combining.the.processability.and.mechanical.properties.of.the.polymer.. matrices.
with. the. electronic,. magnetic,. and. optic. properties. of. ICPs. (Barra. et. al..
2001)..Also,.since.the.mid-1980s,.several.air-stable.ICPs,.such.as.polypyrrole.
(PPy),. poly(3,4-ethylene. dioxythiophene). (PEDOT),. polyaniline. (PAni),. and.
poly(thiophene).(Pt).have.been.explored.in.many.areas.due.to.their.environmental.stability,.ease.of.synthesis,.and.physicochemical.properties.that.can.
be.controlled.by.changing.the.doping.degree.
A.large.number.of.excellent.reviews.on.ICPs.and.their.blends.with.insulating.polymers.have.been.published.(Bhadra.et.al..2009;.De.Paoli.1997)..The.
following.review.is.confined.to.conductive.polymer.blends.for.medical.and.
biological.applications..Research.on.ICPs.for.use.in.biomedical.applications.
has.been.greatly.expanding,.given.the.discovery.that.these.materials.could.
be. (bio)compatible. with. many. biological. molecules. such. as. those. used. in.
biosensors.. ICPs. have. also. been. shown. to. modulate. cellular. activities. via.
electrical. stimulation.. This. effect. includes. cell. adhesion,. migration,. DNA.
synthesis,.and.protein.secretion..Specifically,.many.of.these.studies.involved.
nerve,.bone,.muscle,.and.cardiac.cells,.which.respond.to.electrical.impulses..
Also,. along. with. biocompatibility,. ICPs. have. been. shown. to. be. capable. of.
entrapping.and.controllably.releasing.biological.molecules.to.transfer.charge.
from.biochemical.reactions.(Guimard.et.al..2007;.Ravichandran.et.al..2010).
Polypyrrole.and.polyaniline.will.be.discussed.here.because.they.are.probably.
the.most.extensively.studied.conducting.polymers..Current.results.concerning.
the.preparation,.characterization,.and.properties.of.conductive.porous.nanofibrous. blends. comprised. of. bacterial. nanocellulose. (BNC). containing. polypyrrole.or.polyaniline.are.also.presented.and.compared.with.other.conductive.
porous.nanofibrous.blends.used.for.biological.and.medical.applications.
Conductive Polymer Fibrous Templates
Conductive. polymer. scaffolds. having. fibers. in. the. nanoscale. range. should.
mimic,.up.to.a.determined.level,.the.structural.and.biological.functions.of.
native. cells’. extracellular. matrix.. These. materials. show. great. potential. for.
tissue.engineering.and.therapeutic.applications.given.their.biocompatibility,.
efficient. electrical. charge. transfer. from. bioreactions,. potential. for. carrying.
current. in. biological. environments,. and. the. ability. to. undergo. expansion.
and.contraction.during.electrochemical.redox.reactions..The.in.vitro.and.in.
vivo.cell.and.tissue.compatibility.of.PPy.and.PAni.scaffolds.has.been.demonstrated..Earlier.studies.also.showed.that.PAni.supports.the.adhesion.and.
proliferation.of.H9c2.cardiac.myoblasts,.COS.fibroblast.cells,.and.PC12.cells,.
while.PPy.is.cytocompatible.with.mouse.fibroblasts.and.neuroblastoma.cells.
(Ghasemi-Mobarakeh.et.al..2009;.Gizdavic-Nikolaidis.et.al..2010;.Li.et.al..2006).
extrinsic.approach.has.been.receiving.increasing.attention,.as.it.allows.combining.the.processability.and.mechanical.properties.of.the.polymer.. matrices.
with. the. electronic,. magnetic,. and. optic. properties. of. ICPs. (Barra. et. al..
2001)..Also,.since.the.mid-1980s,.several.air-stable.ICPs,.such.as.polypyrrole.
(PPy),. poly(3,4-ethylene. dioxythiophene). (PEDOT),. polyaniline. (PAni),. and.
poly(thiophene).(Pt).have.been.explored.in.many.areas.due.to.their.environmental.stability,.ease.of.synthesis,.and.physicochemical.properties.that.can.
be.controlled.by.changing.the.doping.degree.
A.large.number.of.excellent.reviews.on.ICPs.and.their.blends.with.insulating.polymers.have.been.published.(Bhadra.et.al..2009;.De.Paoli.1997)..The.
following.review.is.confined.to.conductive.polymer.blends.for.medical.and.
biological.applications..Research.on.ICPs.for.use.in.biomedical.applications.
has.been.greatly.expanding,.given.the.discovery.that.these.materials.could.
be. (bio)compatible. with. many. biological. molecules. such. as. those. used. in.
biosensors.. ICPs. have. also. been. shown. to. modulate. cellular. activities. via.
electrical. stimulation.. This. effect. includes. cell. adhesion,. migration,. DNA.
synthesis,.and.protein.secretion..Specifically,.many.of.these.studies.involved.
nerve,.bone,.muscle,.and.cardiac.cells,.which.respond.to.electrical.impulses..
Also,. along. with. biocompatibility,. ICPs. have. been. shown. to. be. capable. of.
entrapping.and.controllably.releasing.biological.molecules.to.transfer.charge.
from.biochemical.reactions.(Guimard.et.al..2007;.Ravichandran.et.al..2010).
Polypyrrole.and.polyaniline.will.be.discussed.here.because.they.are.probably.
the.most.extensively.studied.conducting.polymers..Current.results.concerning.
the.preparation,.characterization,.and.properties.of.conductive.porous.nanofibrous. blends. comprised. of. bacterial. nanocellulose. (BNC). containing. polypyrrole.or.polyaniline.are.also.presented.and.compared.with.other.conductive.
porous.nanofibrous.blends.used.for.biological.and.medical.applications.
Conductive Polymer Fibrous Templates
Conductive. polymer. scaffolds. having. fibers. in. the. nanoscale. range. should.
mimic,.up.to.a.determined.level,.the.structural.and.biological.functions.of.
native. cells’. extracellular. matrix.. These. materials. show. great. potential. for.
tissue.engineering.and.therapeutic.applications.given.their.biocompatibility,.
efficient. electrical. charge. transfer. from. bioreactions,. potential. for. carrying.
current. in. biological. environments,. and. the. ability. to. undergo. expansion.
and.contraction.during.electrochemical.redox.reactions..The.in.vitro.and.in.
vivo.cell.and.tissue.compatibility.of.PPy.and.PAni.scaffolds.has.been.demonstrated..Earlier.studies.also.showed.that.PAni.supports.the.adhesion.and.
proliferation.of.H9c2.cardiac.myoblasts,.COS.fibroblast.cells,.and.PC12.cells,.
while.PPy.is.cytocompatible.with.mouse.fibroblasts.and.neuroblastoma.cells.
(Ghasemi-Mobarakeh.et.al..2009;.Gizdavic-Nikolaidis.et.al..2010;.Li.et.al..2006).