Biomedical Engineering Reference
In-Depth Information
wereobservedinthecollagenspongereinforcedwithPGAfiberthan
in collagen sponge that did notcontain PGA fiber.
8
,
62
,
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Recent studies have been conducted to evaluate the use of chi-
tosan, calcium phosphate cement (CPC), and biodegradable poly-
mers,suchasVicrylTMmeshorpoly-glactinmesh.Theknittedmesh
effectively improved the load-bearing behavior of scaffolds, and in
the case of chitosan and CPC scaffolds reinforced with mesh, the
strength increased by about tenfold when compared with unrein-
forced CPC scaffolds. These studies demonstrate that a PCL scaf-
fold reinforced with PLLA fiber could be useful for bone tissue
engineering.
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−
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28.3.3
Bioartificial Vessel
The use of several synthetic vascular conduits has been evaluated,
but these have proven to be thrombogenic to some extent and have
no growth potential. Additionally, these synthetic materials eventu-
allyrequirereplacementbecauseofeitherseverestenosisatthesite
of conduct implantation due to calcification or complications from
sizediscrepancies that occur as the patients grow.
67
Using the classical tissue engineering precedent, cells can be
seeded onto a biodegradable scaffold that provides sites for cell
attachment andspace for neotissueregeneration.
68
Various artificial vessels constructed of biodegradable materi-
als have also been evaluated. Some researchers have constructed
tube-shaped reinforced scaffolds composed of L-lactide and
ε
-
carprolactone (PCL) withPGA nonwovenfabric sheets.
67
,
69
These tissue-engineered reinforced scaffolds were surgically
implanted into dogs after being cultured with autolgous vascu-
lar myofibroblasts and smooth muscle cells for one week. The
implantedtissue-engineeredscaffoldsshowednoevidenceofsteno-
sis, dilatation, or thrombus, and their overall gross appearance was
similar to that of nativeveins.
67
Recent studies were conducted to evaluate the use of collagen,
a PGA mesh, and a PLA mesh. These scaffolds were fabricated by
compounding a collagen sponge with a PGA knitted mesh that was
reinforced on the outside withwoven PLA (Fig. 28.4).
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