Barbieri Thesis - BioMedical Materials program (BMM)

CChapter
3 – Instructive
composit tes: effect of filller
content on osteoinduction
Thus, fillingg
the polymerr
with high per
phosphate apatite particcles
can rend
could be relevant wheen
implanting
osteoinducction
is requireed.
and 6 weeeks
after imp
materials ssuch
as bipha
the same animal mode
osteoinducction
in the 40%
[86, 238, 304] T
plantation, wh
asic calcium p
els. [219] rcentage (i.e. up to 40%wt. .) of nano–sized
calcium
der poly(D,L–llactide)
osteo oinductive. This
property
g these mateerials
in large
bone defe ects where
The bone induuction
in 40% CaP started between 3
ich is a time comparable to other oste eoinductive
phosphate (BCCP)
and hydro oxyapatite (HA A), used in
Howev ver, at present
it is not fully f clear what
triggers
% CaP compo osites.
Figure 5. (aa)
FTIR spectraa
of the compos sites. It can bee
observed that the intensity of f the apatite
characteristicc
peaks increasess
with the apatite e content in the coomposites
(red box), b while one of f the peaks of
poly(D,L–lacttide)
disappears with the decreas se of the polymerr
content (green box). (b) Change es of calcium
ion concentraation
of SPS whhen
the samples were soaked inn
it for eight hou urs. On the diagram
the final
average calciium
ion concentrrations
in SPS are e reported for eacch
material.
Figure 6. Suurface
mineralization
was seen af fter two days on 40% CaP, while e it did not occur on the other
composites aafter
two weeks. ( (a) 40% CaP surface
before soakking
in SBF and (b) ( 40% CaP afte er two days in
SBF when ssurface
mineralizzation
was occu urring. (c) 40% CaP after 14 days d when the surface was
completely ccovered
by thick mineralized lay yers. Images (d) , (e) and (f) show
0%, 10% an nd 20% CaP
respectively aafter
14 days in SSBF.
In the small boxes are the sttarting
surfaces of o 0%, 10% and 20% 2 CaP.
63