Biomedical Engineering Reference
In-Depth Information
Figure28.4. Formationofabiodegradablescaffoldreinforcedwithwoven
a PLA mesh (arrow) cross-linked with collagen sponge (a). Scanning elec-
tron microscopy image of the tissue-engineered patch shows the uniformly
distributedandinterconnectedporestructure(poresize50-150 μ m)ofthe
collagen sponge (b)(magnification 40x). (Watanabe et al. 67 )
Thescaffoldswerethengraftedintotheporcinedescending
aorta, the porcine pulmonary arterial trunk, or the canine ventric-
ular outflow tract. The results of this study demonstrated that there
was no thrombus formation and this scaffold provided good in situ
regeneration. 70 When combined with the results of the aforemen-
tioned studies, these findings indicate that these reinforced scaf-
folds can be used as surgical scaffolds for the repair of vascular
defects.
28.3.4 Bioartificial Tracheae
Tissue-engineered tracheal tissue requires a scaffold that can main-
tain its specific shape and size in vivo . Many types of scaffolds have
been used in attempts to repair tracheal defects, but these have had
limited success because of graft ischemia and inflammatory reac-
tions leading to anastomotic dehiscence and stenosis. 71 Addition-
ally, tissue-engineered tracheae have been found to be incapable of
providing enough mechanical strength, which led to stenotic com-
plications. Therefore, scaffolds used to generate tracheae should be
designed to maintain their shape during the initial surgery and pro-
vide enough mechanical strength to prevent collapse. 72
Fabricating a PLGA scaffold in a specific shape involves coating a
fibrous PGA mesh with solutions of PLA and then allowing the sol-
vent to evaporate so that PLA is deposited on the mesh. However,
despite the increased mechanical properties, it is unlikely that the
 
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