Biomedical Engineering Reference
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it was present in the extracellular matrix after four weeks and
increasedwithtime.Theproliferatedchondrocytesandthesecreted
extracellular matrices constructed new articular cartilage-like tis-
sue. The scaffold slowly degraded, losing almost 36.9% of its mass
after 10 weeks.
In vivo subcutaneous implantation in nude mice showed that a
more homogeneous articular cartilage-like tissue was formed in the
hybrid sponge than in the PLGA sponge. New tissues that formed
in the hybrid sponges maintained the same shape as that of the
hybrid sponge. The PLGA sponge also maintained its original shape
after implantation. However, the control collagen sponge collapsed
when implanted in the nude mice. Suppression of the surrounding
tissues and contraction of the new tissue resulted in the collapse
of the collagen sponge. The mechanically strong PLGA sponge and
PLGA-collagen hybrid sponges protected themselves from deforma-
tion and collapse during in vivo implantation.
From the above results, it can be concluded that the PLGA-
collagen hybrid sponge shows high mechanical properties and good
cell interaction and thus promotes new tissue formation when used
for tissue engineering. The PLGA-collagen hybrid sponge combines
the advantages of both synthetic PLGA and naturally derived colla-
gen. The hybridization method can also be used to prepare hybrid
scaffoldsofotherbiodegradablesyntheticpolymersandothernatu-
rally derived polymers.
22.3 PLGA-Collagen Hybrid Mesh
A mesh-type hybrid scaffold of biodegradable synthetic polymers
and collagen has been developed by introducing weblike collagen
microsponges in the openings of a mesh of biodegradable synthetic
polymers(Fig.22.3). 14 APLGA-collagenhybridmeshisoneexample
of such a kind of mesh-type hybrid scaffold (Fig. 22.4). The forma-
tion of collagen microsponges in the openings of the PLGA mesh is
obtainedbyintroducinganaqueouscollagensolutionintotheopen-
ings, freeze-drying, and cross-linking. After these procedures, web-
like collagen microsponges form in the openings of the synthetic
PLGA mesh. SEM observation showed that collagen microsponges
 
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