131
Nematic Ordered Cellulose Templates
of.a.blend.of.cellulose.and.O-methylcellulose.with.DS.1.6.(50/50.w/w).that.
has.been.unixially.stretched.in.the.same.manner.for.NOC..The.bacteria.also.
tend.to.follow.the.molecular.tracks.on.the.surface.of.the.oriented.cellulosic.
blend.template,.similar.to.the.NOC.case..In.addition,.the.bacteria.exhibit.similar.linear.movements.along.the.molecular.tracks.on.NOC/cellulose.. acetate.
(DS 1.7).templates.as.the.NOC..That.is,.the.NOC.blends.as.well.as.NOC.are.
supposed.to.show.similar.unique.properties.as.templates.that.direct.the.bacterial.movement..When.Gluconacetobacter.cells.are.placed.on.an.agar.surface.
as.a.control,.their.interaction.seems.to.be.reduced,.and.twisted.nanofibers.
are.always.deposited,.also.in.a.random.fashion..It.should.be.noted.that.this.
regulated.movement.of.the.bacterium.is.not.observed.in.the.synthetic.polymers.having.OH.groups,.such.as.polyvinyl.alcohol,.but.only.in.the.nematic.
ordered.states.of.carbohydrate.polymers.described.earlier.(Kondo.et.al..2002).
Critical Factors in Biodirected Epitaxial
Nanodeposition on Molecular Tracks
Hierarchical Order
Figures 6.12a–b.show.AFM.images.before.and.after.incubation.of.Gluconacetobacter.
cells.showing.fabrication.of.a.3D.architecture.along.the.molecular.tracks.of.NOC.
as. a. scaffold.. After. culturing. for. 10. h. (Figure 6.12b),. the. height. increased. by.
10 times,.to.approximately.350.nm,.selectively.in.the.stripes.on.the.NOC..This.is.
evidence.of.the.directed.close.contact.between.the.secreted.nanofibers.and.the.
molecular.tracks.on.NOC.templates..Moreover,.the.elastic.modulus.increased.
slightly.from.6.2.±.0.1.GPa.to.6.9.±.0.0.GPa.by.patterned.fabrication.with.the.
secreted. cellulose. nanofibers. on. the. NOC. surface.. Presumably. the. change. is.
mostly.influenced.by.the.sufficient.strength.of.NOC.as.a.scaffold.when.compared.with.the.deposited.nanofibers.on.the.above..Here.one.can.observe.that.the.
additional.layers.secreted.over.time.continue.to.mimic.the.original.orientation. .
initiated.in.the.first.deposited.layer.(e.g.,.the.epitaxial.deposition).
epitaxial Deposition
The.adhesion.occurs.between.biosynthesized.cellulose.microfibrils.and.the.
C6. primary. OH. groups. and/or. hydrophobic. tracks. described. previously..
The.important.factor.for.controlling.bacterial.movements.may.be.close.contact.and.strong.interaction.between.the.molecular.tracks.on.NOC.and.the.
newly.synthesized. cellulose. microfibrils.. A. schematic. explaining. this. concept.is.shown.in.Figure 6.13..Normally.G. xylinus secretes.a.cellulose.nanofiber.that.comprises.a.microfibril.approximately.3.5.nm.in.width,.as.shown.
in.Figure 6.13.(left)..The.microfibrils.from.the.subunit.of.terminal.complexes.
Nematic Ordered Cellulose Templates
of.a.blend.of.cellulose.and.O-methylcellulose.with.DS.1.6.(50/50.w/w).that.
has.been.unixially.stretched.in.the.same.manner.for.NOC..The.bacteria.also.
tend.to.follow.the.molecular.tracks.on.the.surface.of.the.oriented.cellulosic.
blend.template,.similar.to.the.NOC.case..In.addition,.the.bacteria.exhibit.similar.linear.movements.along.the.molecular.tracks.on.NOC/cellulose.. acetate.
(DS 1.7).templates.as.the.NOC..That.is,.the.NOC.blends.as.well.as.NOC.are.
supposed.to.show.similar.unique.properties.as.templates.that.direct.the.bacterial.movement..When.Gluconacetobacter.cells.are.placed.on.an.agar.surface.
as.a.control,.their.interaction.seems.to.be.reduced,.and.twisted.nanofibers.
are.always.deposited,.also.in.a.random.fashion..It.should.be.noted.that.this.
regulated.movement.of.the.bacterium.is.not.observed.in.the.synthetic.polymers.having.OH.groups,.such.as.polyvinyl.alcohol,.but.only.in.the.nematic.
ordered.states.of.carbohydrate.polymers.described.earlier.(Kondo.et.al..2002).
Critical Factors in Biodirected Epitaxial
Nanodeposition on Molecular Tracks
Hierarchical Order
Figures 6.12a–b.show.AFM.images.before.and.after.incubation.of.Gluconacetobacter.
cells.showing.fabrication.of.a.3D.architecture.along.the.molecular.tracks.of.NOC.
as. a. scaffold.. After. culturing. for. 10. h. (Figure 6.12b),. the. height. increased. by.
10 times,.to.approximately.350.nm,.selectively.in.the.stripes.on.the.NOC..This.is.
evidence.of.the.directed.close.contact.between.the.secreted.nanofibers.and.the.
molecular.tracks.on.NOC.templates..Moreover,.the.elastic.modulus.increased.
slightly.from.6.2.±.0.1.GPa.to.6.9.±.0.0.GPa.by.patterned.fabrication.with.the.
secreted. cellulose. nanofibers. on. the. NOC. surface.. Presumably. the. change. is.
mostly.influenced.by.the.sufficient.strength.of.NOC.as.a.scaffold.when.compared.with.the.deposited.nanofibers.on.the.above..Here.one.can.observe.that.the.
additional.layers.secreted.over.time.continue.to.mimic.the.original.orientation. .
initiated.in.the.first.deposited.layer.(e.g.,.the.epitaxial.deposition).
epitaxial Deposition
The.adhesion.occurs.between.biosynthesized.cellulose.microfibrils.and.the.
C6. primary. OH. groups. and/or. hydrophobic. tracks. described. previously..
The.important.factor.for.controlling.bacterial.movements.may.be.close.contact.and.strong.interaction.between.the.molecular.tracks.on.NOC.and.the.
newly.synthesized. cellulose. microfibrils.. A. schematic. explaining. this. concept.is.shown.in.Figure 6.13..Normally.G. xylinus secretes.a.cellulose.nanofiber.that.comprises.a.microfibril.approximately.3.5.nm.in.width,.as.shown.
in.Figure 6.13.(left)..The.microfibrils.from.the.subunit.of.terminal.complexes.