Figure 4.8
83
Tough Bacterial Nanocellulose Hydrogels Based on the Double-Network
radation.within.the.living.body.is.discussed.to.understand.the.applicability.of.these.gels.as.a.potential.cartilage.material.
Wear Property of DN gels in the Pin-On Flat Test
The.maximum.wear.depth.of.the.BNC-PDMAAm.gel.and.BNC-gelatin.gel.
along.with.some.other.DN.gels.such.as.PAMPS-PAAm.and.PAMPS-PDMAAm.
gel.using.the.pin-on.flat-type.wear.test.is.evaluated..In.addition,.these.properties.were.compared.with.the.maximum.wear.depth.of.ultrahigh.molecular.
weight.polyethylene.(UHMWPE),.which.is.currently.used.in.artificial.joints..
During. wear. testing,. the. apparent. friction. coefficient. varied.. There. were.
no. significant. differences. in. the. friction. coefficient. among. PAMPS-PAAm,.
PAMPS-PDMAAm,.BNC-PDMAA,.and.UHMWPE..On.the.other.hand,.the.
friction.coefficient.of.the.BNC-gelatin.gel.was.significantly.higher.than.that.
of.the.others.(p.=.0.001).(Yasuda.et.al..2005).
In. gross. observations. after. the. wear. tests. (Figure 4.8),. a. mildly. concave.
lesion.appeared.on.the.surface.of.each.specimen.of.the.PAMPS-PAAm.gel.and.
the.BNC-PDMAA.gel,.while.a.severely.concave.lesion.appeared.on.the.surface.
of.each.BNC-gelatin.gel.specimen..On.the.surface.of.the.concave.lesion.there.
were. a. number. of. scratches. that. were. aligned. parallel. to. the. sliding. . direction.. The. PAMPS-PDMAAm. gel. specimens. and. UHMWPE. specimens. did.
not.show.an.obviously.concave.lesion.on.the.surface,.although.the.UHMWPE.
specimens.showed.a.lesion.that.appeared.to.shine.
In. the. evaluation. of. the. maximum. wear. depth. with. the. confocal. laser.
m . icroscope.(Table 4.2),.the.mean.value.was.minimal.in.the.PAMPS-PDMAAm.
gel.(3.20.μm).and.in.the.UHMWPE.(3.33.μm)..There.was.no.significant.difference.between.the.two.materials..The.PAMPS-PAAm.gel.(9.50.μm).and.
the.BNC-PDMAAm.gel.(7.80.μm).showed.two.to.three.times.the.depth.of.
the.UHMWPE..The.BNC-gelatin.gel.showed.a.tremendous.amount.of.wear.
(1302.40.μm)..There.were.significant.differences.between.one.of.these.three.
gels.and.UHMWPE..The.surface.of.each.gel.material.was.extremely.smooth.
(a)
(b)
Figure 4.8
Gross.observations.of.representative.samples.after.the.wear.tests..(a).BNC–PDMAAm.DN.gel,.
and.(b).BNC-gelatin.DN.gel..(Reproduced.with.permission.of.Yasuda.et.al..2005.)
83
Tough Bacterial Nanocellulose Hydrogels Based on the Double-Network
radation.within.the.living.body.is.discussed.to.understand.the.applicability.of.these.gels.as.a.potential.cartilage.material.
Wear Property of DN gels in the Pin-On Flat Test
The.maximum.wear.depth.of.the.BNC-PDMAAm.gel.and.BNC-gelatin.gel.
along.with.some.other.DN.gels.such.as.PAMPS-PAAm.and.PAMPS-PDMAAm.
gel.using.the.pin-on.flat-type.wear.test.is.evaluated..In.addition,.these.properties.were.compared.with.the.maximum.wear.depth.of.ultrahigh.molecular.
weight.polyethylene.(UHMWPE),.which.is.currently.used.in.artificial.joints..
During. wear. testing,. the. apparent. friction. coefficient. varied.. There. were.
no. significant. differences. in. the. friction. coefficient. among. PAMPS-PAAm,.
PAMPS-PDMAAm,.BNC-PDMAA,.and.UHMWPE..On.the.other.hand,.the.
friction.coefficient.of.the.BNC-gelatin.gel.was.significantly.higher.than.that.
of.the.others.(p.=.0.001).(Yasuda.et.al..2005).
In. gross. observations. after. the. wear. tests. (Figure 4.8),. a. mildly. concave.
lesion.appeared.on.the.surface.of.each.specimen.of.the.PAMPS-PAAm.gel.and.
the.BNC-PDMAA.gel,.while.a.severely.concave.lesion.appeared.on.the.surface.
of.each.BNC-gelatin.gel.specimen..On.the.surface.of.the.concave.lesion.there.
were. a. number. of. scratches. that. were. aligned. parallel. to. the. sliding. . direction.. The. PAMPS-PDMAAm. gel. specimens. and. UHMWPE. specimens. did.
not.show.an.obviously.concave.lesion.on.the.surface,.although.the.UHMWPE.
specimens.showed.a.lesion.that.appeared.to.shine.
In. the. evaluation. of. the. maximum. wear. depth. with. the. confocal. laser.
m . icroscope.(Table 4.2),.the.mean.value.was.minimal.in.the.PAMPS-PDMAAm.
gel.(3.20.μm).and.in.the.UHMWPE.(3.33.μm)..There.was.no.significant.difference.between.the.two.materials..The.PAMPS-PAAm.gel.(9.50.μm).and.
the.BNC-PDMAAm.gel.(7.80.μm).showed.two.to.three.times.the.depth.of.
the.UHMWPE..The.BNC-gelatin.gel.showed.a.tremendous.amount.of.wear.
(1302.40.μm)..There.were.significant.differences.between.one.of.these.three.
gels.and.UHMWPE..The.surface.of.each.gel.material.was.extremely.smooth.
(a)
(b)
Figure 4.8
Gross.observations.of.representative.samples.after.the.wear.tests..(a).BNC–PDMAAm.DN.gel,.
and.(b).BNC-gelatin.DN.gel..(Reproduced.with.permission.of.Yasuda.et.al..2005.)