Bacterial Nanocellulose as a Structured Platform for Conductive Biopolymers 255
Major. challenges. include. the. production. of. self-assembled. semipermeable.thick.membranes;.anisotropic.internal.nanofiber.arrangement;.adequate.
porosity. and. appropriate. internal. channel. network;. full. compatibility. with.
hydrophilic. fluids;. biointegration. with. polysaccharides,. proteins,. and. other.
biologically. active. structural. molecules. and. polymers;. suitability. to. sustain.
cell.attachment.and.growth;.moldability;.and.scaling-up..Advances.in.innovative. biomaterials. design. are. moving. toward. feasible. and. low-cost. processes.
of.mimicking.extracellular.matrices.(ECMs).(Bierwolf.et.al..2009;.Chung.et al..
ural.approaches.have.being.successfully.applied.to.produce.new.biocompatible.ECM-like.materials.(Gillette.et.al..2008;.Kopecek.and.Yang.2009;.Mitragotri.
and. Lahann. 2009;. Stalling. et. al.. 2009;. Zeugolis. et al.. 2008).. Therefore. the.
design.of.novel.scaffolds.(supports.that.allow.surrounding.cells.to.migrate.
into. them,. regenerating. the. damaged. tissue). with. adequate. micromorphology.are.the.main.challenge.in.the.actual.tissue.engineering.concept,.which.
includes.. specific.properties.for.cell.adhesion.and.new.tissue.formation.
Recent.advances.of.biomaterials.in.tissue.engineering.include.the.development.of.functionalized.ECM-like.scaffolds.coated.with.biomaterials,.such.as.
hydroxyapatite,. polyaniline,. or. polypyrrole. (Kamalesh. et. al.. 2000;. Li. et. al..
2006;.Muller.et.al..2010;.Recouvreux.et.al..2009).to.name.a.few..Conductive.
PPy.coatings.on.nanofibers.acting.as.an.active.interface.for.tissue.engineering.may.be.used.to.regulate.cell.activity.through.electrical.stimulation.
To. demonstrate. the. potential. of. BNC/PPy·FeCl 3 . membranes. produced.
by. in. situ. polymerization. as. scaffold. for. tissue. engineering. applications,.
cell.seeding,.and.attachment.they.were.used.as.templates.for.seeding.L929.
mouse.connective.tissue,.which.are.fibroblast-like.cells..Cell.suspension.was.
directly.seeded.(8.×.10 5 .cells).onto.the.surfaces.of.the.BNC/PPy.membranes..
After.72.h.incubation,.the.membranes.with.attached.cells.were.washed.with.
phosphate. buffered. saline. (PBS). and. fixed. with. glutaraldehyde. 2.5%.. The.
samples. were. subsequently. dehydrated. with. ethanol. and. dried.. The. scaffolds. were. gold. sputtered. and. examined. by. SEM. to. evaluate. the. cellular.
morphology.and.surface.behavior.of.the.L929.cells.
SEM. micrographs. of. cell-seeded. BNC/PPy. (Figure  12.11). membranes.
revealed. that. the. fibroblasts. are. homogeneously. distributed. over. the. surface.(Figures 12.11a.and.12.11b)..Fibroblasts.with.connected.nascent.daughter.
cells. are. also. observed. (Figures  12.11c. and. 12.11d),. indicating. that. cells. on.
BNC/PPy.fibers.are.being.actively.divided..Image.analyses.showed.that.cells.
are.being.attached.and.grown.throughout.the.BNC/PPy.membranes,.which.
suggests.an.inducible.tissue.reconstruction..The.unique.properties.of.BNC.
combined.with.the.conductive.properties.of.PPy.may.be.interesting.for.tissue.
engineering. applications. that. require. electrical. conductivity.. BNC. fibrous.
membranes.coated.with.conductive.polymers.may.potentially.be.implanted.
directly.in.neuronal.tissue-deficient.regions.or.used.as.cell-carrier.scaffolds.
for.therapeutic.and.regenerative.tissue.applications..The.BNC/PPy.composite.can.also.be.used.as.platforms.for.3D.cell.cultures.for.in.vitro.human.cell.