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Biomimetic Mineralization of Apatite on Bacterial Cellulose
mimicking.the.mineralization.system.of.natural.bone,.with.some.successful.
outcomes..However,.the.search.for.an.ideal.biomaterial.with.properties.and.
functionalities.similar.to.natural.bone.is.a.continuing.process.because.no.single.material.can.satisfy.all.the.requirements.for.creating.optimal.scaffolding.
properties,. such. as. strength,. toughness,. osteoconductivity,. osteoinductivity,.
controlled. degradation,. inflammatory. response,. and. deformability.. In. this.
study,. the. ultrafine. 3D. BC. network. structure. with. its. native. unique. properties. is. exploited. to. fabricate. hybrid. materials. analogous. to. natural. bone..
Our. study. showed. that. the. formation. of. apatite. is. dependent. on. the. presence.and.type.of.surface.functional.groups.in.the.BC.microfibrillar.network,.
that. is,. the. hydroxyl. (OH). functional. groups. induced. the. progressive. mineralization. process. and. carboxylate. (COO − ). functional. groups. induced. the.
multi. plication.mineralization.process,.whereas.the.presence.of.incorporated.
N-acetylglucosamine.(GlcNAc).hindered.the.rate.of.the.nucleation.process.
Modification. of. BC. by. the. incorporation. of. lysozyme-susceptible. sugar.
units.(GlcNAc).was.performed.during.microbial.synthesis,.considering.the.
analogue.of.biomimetic.extracellular.matrix.as.well.as.enhancing.the.degradation.property.of.BC..It.is.expected.that.the.modified.BC.will.become.more.
relevant.for.end.use,.for.instance,.in.the.biomedical.area..However,.even.a.
small.amount.(0.03–0.36.mole%).of.GlcNAc-incorporated.BC.showed.a.rather.
slow. mineralization. process. compared. with. the. mineralization. process. of.
BC. having. surface. functional. groups. like. OH. and. COO − .. Further. investigations.are.needed.to.tailor.the.surface.properties.of.BC.to.meet.the.main.
criteria.of.mineralized.collagen.composites.such.as.bone.and.teeth,.and.also.
should.be.complemented.by.in.vitro.and.in.vivo.degradation.studies.
Acknowledgments
This.research.was.supported.by.the.Japan.Society.for.the.Promotion.of.Science.
(JSPS).(Grant-in-aid.for.Scientific.Research.16004160).and.the.RISH-Mission.
project. (2006–2007. fiscal. years),. the. Center. for. Exploratory. Research. on.
Humanosphere,.and.the.Research.Institute.for.Sustainable.Humanosphere.
at.Kyoto.University..Shigeru.Yamanaka.from.Shinshu.University.is.thanked.
for.the.generous.gift.of.the.Acetobacter.strain.used.in.this.study..T. T..Nge.
thanks.Akira.Isogai.and.Tsuguyki.Saito.(University.of.Tokyo).for.their.guidance.in.conducting.conductimetric.titration;.Vincent.Bulone.(KTH,.Sweden).
and. Takefumi. Hattori. (RISH,. Kyoto. University). for. their. guidance. in. conducting.the.radiolabeling.experiments;.Yuji.Imamura,.Tsuyoshi.Yoshimura,.
and. Won-Joung. Hwang. (RISH,. Kyoto. University). for. their. help. in. using.
the. ICP-AES. facility;. and. Teruo. Kawada. (Graduate. School. of. Agriculture,.
Kyoto.University).and.Hiroyuki.Yano.(RISH,.Kyoto.University).for.the.use.
of.FE-SEM.imaging.