Figure 11.5
232
Bacterial Cellulose
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
Figure 11.5
FE-SEM.images.of.apatite-deposited.BC.surfaces.after.5.cycles.of.alternate.soaking.in.calcium.
and. phosphate. solutions.. (a). Native-BC,. (b). BC-TEMPO,. (c). BC-TEMPO-Ca,. (d). BC-GlcNAc.
(M1604-1604A),.(e).BC-GlcNAc.(M1010-1010A),.(f).BC-GlcNAc.(M0416-0416A).and.magnified.view.
of.apatite.globules.formed.on.the.lower.surfaces.of.the.(g).BC-TEMPO,.(h).BC-TEMPO-Ca,.and.
(i) BC-GlcNAc.(M0020-1010B).template..Scale.bars,.2.μm.for.a-f.and.500.nm.for.g-i..Source:.Adapted.
from.Nge.et.al.,.Biopolymers.(ISBN:978-953-307-109-1,.InTech.,.2010),.345–368,.with.permission.
formed.on.the.BC-GlcNAc.templates..Figure 11.5i.shows.the.typical.morphology.of.apatite.formed.on.the.lower.surface.layer.in.all.BC-GlcNAc.templates,.
where.the.mineral.nucleation.took.place.around.the.surface.of.each.microfibril/bundle..The.apatite-coated.microfibril.diameter.(width).was.found.to.
be.approximately.1.μm..Based.on.the.observed.lateral.dimensions.of.fibril.
nate.soaking.cycles.(approximately.5.h).of.apatite.coating,.the.mineral.deposition.rate.can.be.estimated.to.be.3.nm/min..These.interesting.observations.
of.apatite.morphology.with.respective.BC.templates.indicate.that.the.surface.
properties.of.BC.can.be.tailored.by.modifying.the.BC.during.biosynthesis.
The.Ca:P.molar.ratios.of.BC.templates.determined.by.ICP-AES.are.shown.
in.Table 11.3..The.OCP.or.OCP-like.Ca-P.phase.was.likely.to.form.after.three.
cycles..All.Ca:P.ratios.after.five.cycles.were.lower.than.the.theoretical.value.of.
hydroxyapatite.(1.67),.similar.to.the.values.of.BC.templates.soaked.in.1.5 SBF,.
and. the. Ca-P. phase. formed. on. all. BC. templates. was. a. calcium-deficient.
hydroxyapatite.. The. BC-GlcNAc. samples. that. were. produced. from. the.
M0416. medium. (glucose:GlcNAc. =. 0.4:1.6. g/100. ml). inoculated. with. any.
232
Bacterial Cellulose
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
Figure 11.5
FE-SEM.images.of.apatite-deposited.BC.surfaces.after.5.cycles.of.alternate.soaking.in.calcium.
and. phosphate. solutions.. (a). Native-BC,. (b). BC-TEMPO,. (c). BC-TEMPO-Ca,. (d). BC-GlcNAc.
(M1604-1604A),.(e).BC-GlcNAc.(M1010-1010A),.(f).BC-GlcNAc.(M0416-0416A).and.magnified.view.
of.apatite.globules.formed.on.the.lower.surfaces.of.the.(g).BC-TEMPO,.(h).BC-TEMPO-Ca,.and.
(i) BC-GlcNAc.(M0020-1010B).template..Scale.bars,.2.μm.for.a-f.and.500.nm.for.g-i..Source:.Adapted.
from.Nge.et.al.,.Biopolymers.(ISBN:978-953-307-109-1,.InTech.,.2010),.345–368,.with.permission.
formed.on.the.BC-GlcNAc.templates..Figure 11.5i.shows.the.typical.morphology.of.apatite.formed.on.the.lower.surface.layer.in.all.BC-GlcNAc.templates,.
where.the.mineral.nucleation.took.place.around.the.surface.of.each.microfibril/bundle..The.apatite-coated.microfibril.diameter.(width).was.found.to.
be.approximately.1.μm..Based.on.the.observed.lateral.dimensions.of.fibril.
nate.soaking.cycles.(approximately.5.h).of.apatite.coating,.the.mineral.deposition.rate.can.be.estimated.to.be.3.nm/min..These.interesting.observations.
of.apatite.morphology.with.respective.BC.templates.indicate.that.the.surface.
properties.of.BC.can.be.tailored.by.modifying.the.BC.during.biosynthesis.
The.Ca:P.molar.ratios.of.BC.templates.determined.by.ICP-AES.are.shown.
in.Table 11.3..The.OCP.or.OCP-like.Ca-P.phase.was.likely.to.form.after.three.
cycles..All.Ca:P.ratios.after.five.cycles.were.lower.than.the.theoretical.value.of.
hydroxyapatite.(1.67),.similar.to.the.values.of.BC.templates.soaked.in.1.5 SBF,.
and. the. Ca-P. phase. formed. on. all. BC. templates. was. a. calcium-deficient.
hydroxyapatite.. The. BC-GlcNAc. samples. that. were. produced. from. the.
M0416. medium. (glucose:GlcNAc. =. 0.4:1.6. g/100. ml). inoculated. with. any.