199
Bacterial Nanocellulose Biomaterials with Controlled Architecture
Biofabrication. of. the. natural. polymer. bacterial. nanocellulose. (BNC). has.
erative.medicine..Some.key.advantages.of.BNC.are.that.it.has.unique.biocompatibility,. mechanical. integrity,. and. hydroexpansivity,. and. is. structurally.
stable.under.a.wide.range.of.conditions.(Bäckdahl.et.al..2006;.Helenius.et al..
2006).. Moreover,. the. movement. of. living. bacteria. can. be. guided. to. leave.
behind. a. network. of. cellulose. nanofibrils. of. almost. any. architecture.. It. is.
thus. ideal. as. a. scaffolding. material. on. which. the. cells. can. be. seeded. for.
regenerative.medicine.applications.
BNC as a Viable Candidate for Tissue Engineering Scaffolds
BNC. is. an. emerging. biomaterial. in. the. important. and. quickly. expanding.
fields.of.personal.care,.medicine,.and.life.sciences.(Gatenholm.and.Klemm.
2010;.Klemm.et.al..2006;.Petersen.and.Gatenholm.2011)..The.nanostructured.
tive.for.cell.attachment,.cell.migration,.and.the.production.of.additional.extracellular.matrices..In.vitro.and.in.vivo.studies.have.shown.that.BNC.implants.
do. not. elicit. any. foreign. body. reaction,. fibrosis,. or. capsule. formation..
Inflammatory.giant.cells.have.not.been.detected.around.BNC.networks.and.
connective.tissue.integrates.well.with.BNC.structures.(Helenius.et.al..2006)..
BNC. is. neither. cytotoxic. nor. genotoxic;. however,. only. a. limited. number. of.
studies.have.evaluated.the.interactions.between.BNC.fibrils.and.surrounding.
cells.and.tissues.(Bodin.et.al..2010;.Esguerra.et.al..2010)..Worldwide,.activities.
have. intensified. in. the. research,. development,. and. application. of. hydrated.
and.partially.dehydrated.BNC.materials.in.biomedical.applications.such.as.
wound.care.and.novel.bioactive.implants.(Lohmann.&.Rauscher.2009)..Other.
applications.include.materials.for.bone.and.cartilage.repair.and.tubular.prototypes.as.grafts.for.vascular.surgery.(Bäckdahl.et.al..2011)..In.all.cases,.BNC.
functions.as.a.three-dimensional.(3D).template.for.in.vitro.and.in.vivo.tissue.
growth.(Czaja.et.al..2006;.Klemm.et al..2006;.Webster.2007;.Yano.et al..2005)..
There. is. also. growing. interest. in. the. potential. of. BNC. as. an. integral. participant.in.the.healing.of.chronic.wounds.through.reduction.of.proteolytic.
enzymes,.cytokines,.and.reactive.oxygen.species..BNC-collagen.composites.
formed.in.situ.have.been.shown.to.reduce.selected.proteases.and.interleukin.production.and.show.distinct.antioxidant.capacity.(Wiegand.et.al..2006)..
Silver.chloride-impregnated.BNC.films.have.been.produced.as.antibacterial.
dressings.from.the.never-dried.material.by.postprocessing.immersion.steps..
Silver.chloride.nanoparticles.were.present.on.the.BNC.fibers.in.quantities.up.
to.21%.w/w.(Wang.et.al..2008)..Silver.nanoparticles.were.prepared.in.situ.by.
the.hydrolytic.decomposition.of.silver.triethanolamine.complexes..Scanning.
electron. microscopy. (SEM). images. and. X-ray. diffraction. patterns. showed.
Bacterial Nanocellulose Biomaterials with Controlled Architecture
Biofabrication. of. the. natural. polymer. bacterial. nanocellulose. (BNC). has.
erative.medicine..Some.key.advantages.of.BNC.are.that.it.has.unique.biocompatibility,. mechanical. integrity,. and. hydroexpansivity,. and. is. structurally.
stable.under.a.wide.range.of.conditions.(Bäckdahl.et.al..2006;.Helenius.et al..
2006).. Moreover,. the. movement. of. living. bacteria. can. be. guided. to. leave.
behind. a. network. of. cellulose. nanofibrils. of. almost. any. architecture.. It. is.
thus. ideal. as. a. scaffolding. material. on. which. the. cells. can. be. seeded. for.
regenerative.medicine.applications.
BNC as a Viable Candidate for Tissue Engineering Scaffolds
BNC. is. an. emerging. biomaterial. in. the. important. and. quickly. expanding.
fields.of.personal.care,.medicine,.and.life.sciences.(Gatenholm.and.Klemm.
2010;.Klemm.et.al..2006;.Petersen.and.Gatenholm.2011)..The.nanostructured.
tive.for.cell.attachment,.cell.migration,.and.the.production.of.additional.extracellular.matrices..In.vitro.and.in.vivo.studies.have.shown.that.BNC.implants.
do. not. elicit. any. foreign. body. reaction,. fibrosis,. or. capsule. formation..
Inflammatory.giant.cells.have.not.been.detected.around.BNC.networks.and.
connective.tissue.integrates.well.with.BNC.structures.(Helenius.et.al..2006)..
BNC. is. neither. cytotoxic. nor. genotoxic;. however,. only. a. limited. number. of.
studies.have.evaluated.the.interactions.between.BNC.fibrils.and.surrounding.
cells.and.tissues.(Bodin.et.al..2010;.Esguerra.et.al..2010)..Worldwide,.activities.
have. intensified. in. the. research,. development,. and. application. of. hydrated.
and.partially.dehydrated.BNC.materials.in.biomedical.applications.such.as.
wound.care.and.novel.bioactive.implants.(Lohmann.&.Rauscher.2009)..Other.
applications.include.materials.for.bone.and.cartilage.repair.and.tubular.prototypes.as.grafts.for.vascular.surgery.(Bäckdahl.et.al..2011)..In.all.cases,.BNC.
functions.as.a.three-dimensional.(3D).template.for.in.vitro.and.in.vivo.tissue.
growth.(Czaja.et.al..2006;.Klemm.et al..2006;.Webster.2007;.Yano.et al..2005)..
There. is. also. growing. interest. in. the. potential. of. BNC. as. an. integral. participant.in.the.healing.of.chronic.wounds.through.reduction.of.proteolytic.
enzymes,.cytokines,.and.reactive.oxygen.species..BNC-collagen.composites.
formed.in.situ.have.been.shown.to.reduce.selected.proteases.and.interleukin.production.and.show.distinct.antioxidant.capacity.(Wiegand.et.al..2006)..
Silver.chloride-impregnated.BNC.films.have.been.produced.as.antibacterial.
dressings.from.the.never-dried.material.by.postprocessing.immersion.steps..
Silver.chloride.nanoparticles.were.present.on.the.BNC.fibers.in.quantities.up.
to.21%.w/w.(Wang.et.al..2008)..Silver.nanoparticles.were.prepared.in.situ.by.
the.hydrolytic.decomposition.of.silver.triethanolamine.complexes..Scanning.
electron. microscopy. (SEM). images. and. X-ray. diffraction. patterns. showed.