Biomedical Engineering Reference
In-Depth Information
Figure 2.3.
SEM micrographs of SiC ceramics obtained from the marine
plants (a, b)
Juncus maritimus
and (c, d)
Zostera marina
and (e, f) the
macroalgae
Laminaria ochroleuca.
of 7
m remain on the surface of
Juncus
-based SiC (Fig. 2.3a,b) and
verylargecavitiesarepreservedinsidetheporousmatrixof
Zostera
-
based SiC (Fig. 2.3c,d). It has been also demonstrated that several
marine macroalgae species can be used as vegetable precursors for
the production of SiC bioinspired materials,
13
for instance,
Lami-
naria ochroleuca, Undaria pinnatifida, Saccorhiza polyschides
,and
Cystoseira baccata
. As an example, details of the microstructure of
algae-derived SiC ceramics is shown in Fig. 2.3e,f.
Finally, it has been reported that mechanical tests
11
,
15
,
16
indi-
cate the suitability of bioderived SiC ceramics for medical devices
in terms of structural requirements, as results compare positively
with the density, elastic modulus, compressive strength, and bend-
ingstrengthofatypicalhumancorticalbone.Forinstance,theroom-
temperature compressive strength in the longitudinal (biological
precursor growth) direction of sapelli-derived bio-SiC is from 1160
±
100 (s.d.) MPa to 210
±
20 (s.d.) MPa; in the radial direction, it
is from 430
±
50 (s.d.) MPa to 120
±
10 (s.d.) MPa, depending on
theamountofinfiltratedresidualSi.Thefracturetoughnessreaches
values between 2 and 3 MPa (m)
1
/
2
, and the elastic modulus ranges
from 25 to 230 GPa.
19
,
20
Therefore, bioinspired SiC ceramics can be
tailored by an appropriate precursor selection, depending on the
requirements of a particular type of bone in the body that should
berepaired.
μ
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