Biomedical Engineering Reference
In-Depth Information
Figure 23.7. SEM micrographs of the surface of the chitosan bead scaf-
folds cultured on chondrocytes after 14 d of culture. (a-d) Entire mor-
phology (magnification × 40) and (e-h) magnified images (magnification
×
400). 7
proliferation of chondrocytes was exhibited only on the surface of
the CS-LN2 and 10B-LN2 bead scaffolds having small-size macrop-
ores but exhibited on both the surface and in the center of the CS-
RT70 and10B-RT70 bead scaffolds havinglarge-size macropores. 7
23.5 Chitosan Hydrogels
Biodegradable thermo-gelling hydrogels that undergo a sol-gel
transition with increasing temperature were studied by many
researchersintissueengineering. 30 Theadvantagesoftheinjectable
hydrogels are that they can fill any shape of a defect, may incorpo-
rate drugs and growth factors by simple mixing, and do not require
invasive surgery. 31 A block copolymer of poly-(ethylene oxide-
propylene oxide-ethylene oxide) (Pluronic, known as Poloxamer) 32
and the chitosan/ β -glycerol phosphate ( β -GP) system are well
known as thermogels. 33 Hoemann et al . reported that the thermo-
gelling hydrogels consisting of chitosan and β -GP and can support
in vitro and in vivo accumulation of cartilage matrix by primary
chondrocytes, while persisting in osteochondral defects at least
one week in vivo . 34 Kim et al . also reported that the bone for-
mation from rat muscle-derived stem cells (rMDSCs) using an
injectable in situ -formingchitosangel in vivo wasexamined,andthe
rMDSCs survived well on the hydrogel created by the in vitro and in
 
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