Biomedical Engineering Reference
In-Depth Information
weight HA gel. The incorporated oligopeptide demonstrated induc-
tion of cell adhesion by mimicking microenvironment of ECM in the
body, and thus better bone tissue regeneration was observed in the
calvarialdefectmodelintherat,whichisimportantinitsapplication
in tissue engineering.
9.5.2
HA-Natural Polymer Hybrid Hydrogels
An HA-natural polymer hydrogel was fabricated via diverse meth-
ods by employing, mainly, chitosan among others. These natural
polymers could be chitosan, dextran, alginate, chondroitin sulfate,
gelatin,collagenandetc.HA-chitosanhydrogelshavebeenreported
bymanyresearchgroupsbecauseoftheirconvenientchemistryand
thebiologicaladvantagesofeachpolymer.
81
−
85
Chitosanhadbiolog-
icalpropertiesincartilageandboneregeneration.Thesimplehydro-
gel formation was obtained by a polyelectrolytic complex of anionic
HA-aldehyde and cationic chitosan for the test of tissue regener-
ation of articular cartilage.
82
A biocompatible and biodegradable
HA-chitosan hybrid hydrogel was also derived from water-soluble
chitosan and oxidized HA on mixing, without a chemical cross-
linking agent. The resulting gelation was attributed to the Schiff
base reaction between the amino and aldehyde groups of chi-
tosanandHA,respectively.TheHA-chitosancomplexdemonstrated
the
in vitro
encapsulation of bovine articular chondrocytes within
the hybrid hydrogel matrix and support of cell survival and cell
retention with chondrocytic morphology, thus indicating the pos-
sibility of its application in cartilage tissue engineering via cell
encapsulation.
AninjectableHA-chitosanhydrogelwasalsoformedviabothsuc-
cinicactivationofchitosan(N-succinyl-chitosan)andperiodateacti-
vation of HA (HA-aldehyde) for its applications in cartilage tissue
engineering via chondrocyte encapsulation.
83
Another type of HA-
chitosan hydrogel was obtained via EDC/NHS coupling chemistry
by further grafting of poly(
N
-
iso
propylacrylamide) with an initia-
tor in order to examine their physicochemical characteristics, for
example, thermorepsonsive gel formation,
in vitro
drug release and
in vivo
pharmacodynamics.
84
The sol-gel transition behavior was
observed as one of the physical property tests, and both hydrophilic
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