x
Preface
place.simultaneously..The.biomechanical.performance.(e.g.,.rupture.pressure).
and. compliance,. along. with. biological. response. (endothelialization,. blood.
compatibility),. are. dependent. on. the. morphology. of. the. fibrillar. network..
The.network.formation.is.affected.by.the.cellulose.assembly,.bacteria.motion,.
and.proliferation.rate..An.understanding.of.the.effects.of.cultivation.conditions.on.BNC.network.formation.is,.therefore,.of.great.importance..This.is.
described.in.Chapter 2.
A. shortcoming. limiting. broad. commercialization. has. been. the. lack. of.
large-scale.production.capacity..Chapter.3.reviews.a.variety.of.approaches.
that. are. available. for. the. generation. of. BNC. in. different. forms,. ranging.
from.batch,.to.fed.batch,.to.continuous.cultivation.methods.applying.typical.bio. reactors.but.also.several.specific.devices..The.choice.of.a.cultivation.
technique.depends.on.the.envisaged.application,.since.the.cellulose.supramolecular.structure.and.its.physical.and.mechanical.properties.are.strictly.
influenced.by.the.production.method.
Because.of.its.unique.structure,.BNC.shows.mechanical.anisotropy.with.a.
high. tensile. modulus. along. the. fiber. layer. direction,. but. a. low. compressive.
modulus. perpendicular. to. the. stratified. direction.. Consequently,. water. is.
e . asily.squeezed.out.of.the.gel.under.slight.compression.and.the.swelling.property.is.not.fully.recovered.due.to.hydrogen-bond.formation.between.cellulose.
fibrils..In.Chapter.4,.a.BNC-based.biocompatible.hydrogel.with.high.mechanical.strength.and.reversible.swelling.following.repeated.compression.cycles.is.
described.. It. was. developed. by. combining. the. BNC. with. natural. polymers.
such.as.gelatin,.as.well.as.synthetic.polymers.such.as.polyacrylamide,.using.
a. method. known. as. the. double-network. technique.. These. gels. exhibit. high.
compressive.fracture.stress.comparable.to.cartilage.and.high.tensile.strength,.
comparable.to.ligament.or.tendon..In.addition,.some.biological.properties.of.
these. gels,. such. as. resistance. against. wear,. bio. degradation,. and. biological.
interactions.within.the.living.body,.are.discussed.with.a.perspective.toward.
its.applicability.as.a.potential.biomaterial.
tions.in.human.and.veterinary.medicine,.odontology,.pharmaceuticals,.acoustic.and.filter.membranes,.biotechnological.devices,.and.in.the.food.and.paper.
industries..Chapter.5.provides.an.introduction.to.the.surface.modifications.
of.BNC..Depending.on.the applications,.chemical.modifications,.incorporation.of.bioactive.molecules,.and.modification.of.the.porosity,.crystallinity,.and.
biodegradability.may.be.obtained,.further.increasing.the.potential.of.BNC.
Chapter. 6. reviews. attempts. to. reveal. the. exclusive. structure–property.
relationship.in.order.to.extend.the.use.of.a.nematic.ordered.cellulose.film.as.
a.functional.template.for.bacterium.culture.and.biomimetic.mineralization..
In.addition,.a.review.is.provided.on.carbohydrate.polymers.with.a.variety.of.
hierarchical.nematic.ordered.states.on.various.scales—so-called.nano/micro.
structures—that.would.allow.development.of.new.functional.ordered.scaffolds..The.regulating.factors.for.the.rate.of.the.microbial.three-dimensional.
buildup.are.also.discussed.
Preface
place.simultaneously..The.biomechanical.performance.(e.g.,.rupture.pressure).
and. compliance,. along. with. biological. response. (endothelialization,. blood.
compatibility),. are. dependent. on. the. morphology. of. the. fibrillar. network..
The.network.formation.is.affected.by.the.cellulose.assembly,.bacteria.motion,.
and.proliferation.rate..An.understanding.of.the.effects.of.cultivation.conditions.on.BNC.network.formation.is,.therefore,.of.great.importance..This.is.
described.in.Chapter 2.
A. shortcoming. limiting. broad. commercialization. has. been. the. lack. of.
large-scale.production.capacity..Chapter.3.reviews.a.variety.of.approaches.
that. are. available. for. the. generation. of. BNC. in. different. forms,. ranging.
from.batch,.to.fed.batch,.to.continuous.cultivation.methods.applying.typical.bio. reactors.but.also.several.specific.devices..The.choice.of.a.cultivation.
technique.depends.on.the.envisaged.application,.since.the.cellulose.supramolecular.structure.and.its.physical.and.mechanical.properties.are.strictly.
influenced.by.the.production.method.
Because.of.its.unique.structure,.BNC.shows.mechanical.anisotropy.with.a.
high. tensile. modulus. along. the. fiber. layer. direction,. but. a. low. compressive.
modulus. perpendicular. to. the. stratified. direction.. Consequently,. water. is.
e . asily.squeezed.out.of.the.gel.under.slight.compression.and.the.swelling.property.is.not.fully.recovered.due.to.hydrogen-bond.formation.between.cellulose.
fibrils..In.Chapter.4,.a.BNC-based.biocompatible.hydrogel.with.high.mechanical.strength.and.reversible.swelling.following.repeated.compression.cycles.is.
described.. It. was. developed. by. combining. the. BNC. with. natural. polymers.
such.as.gelatin,.as.well.as.synthetic.polymers.such.as.polyacrylamide,.using.
a. method. known. as. the. double-network. technique.. These. gels. exhibit. high.
compressive.fracture.stress.comparable.to.cartilage.and.high.tensile.strength,.
comparable.to.ligament.or.tendon..In.addition,.some.biological.properties.of.
these. gels,. such. as. resistance. against. wear,. bio. degradation,. and. biological.
interactions.within.the.living.body,.are.discussed.with.a.perspective.toward.
its.applicability.as.a.potential.biomaterial.
tions.in.human.and.veterinary.medicine,.odontology,.pharmaceuticals,.acoustic.and.filter.membranes,.biotechnological.devices,.and.in.the.food.and.paper.
industries..Chapter.5.provides.an.introduction.to.the.surface.modifications.
of.BNC..Depending.on.the applications,.chemical.modifications,.incorporation.of.bioactive.molecules,.and.modification.of.the.porosity,.crystallinity,.and.
biodegradability.may.be.obtained,.further.increasing.the.potential.of.BNC.
Chapter. 6. reviews. attempts. to. reveal. the. exclusive. structure–property.
relationship.in.order.to.extend.the.use.of.a.nematic.ordered.cellulose.film.as.
a.functional.template.for.bacterium.culture.and.biomimetic.mineralization..
In.addition,.a.review.is.provided.on.carbohydrate.polymers.with.a.variety.of.
hierarchical.nematic.ordered.states.on.various.scales—so-called.nano/micro.
structures—that.would.allow.development.of.new.functional.ordered.scaffolds..The.regulating.factors.for.the.rate.of.the.microbial.three-dimensional.
buildup.are.also.discussed.