Biomedical Engineering Reference
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9.4.1.6 Azaide
In situ chemical gelation of aqueous HA solution has been devel-
oped by grafting with either azaide or alkyne terminal function-
ality through copper-catalyzed azide-alkyne cyclo-addition. Azaide
and alkyne-grafted HAs were obtained by reacting 11-azido-3,6,9-
trioxaundecan-1-amine and proparlgylamine with separate HA via
EDC/NHS chemistry (Fig. 9.24). 78 When these two types of HA
derivatives were mixed together, they gave rise to a 1,3-dipolar
cyclo-addition reaction, showing quick gelation in the presence of
catalyst Cu(I). By carrying out the HA gelation process in aqueous
solutions of benzidamine and doxorubicin, respectively, the swollen
HAhydrogelactedasdrugreservoirs. 78 Thedoxorubicinreleasewas
well-controllable depending on the gel's degree of cross-linking and
degradation. Finally, formation of the self -cross-linking gels using
aqueoussuspensionsof Saccharomices cerevisiae yeastcellsallowed
scaffoldfabrication,insidewhichcellswerehomogeneouslydistrib-
uted and dhered well to the inner pores surfaces. The obtained
HA gels have positive features in the choice of scaffolds for tissue
engineering anddrug delivery systems.
Figure 9.24. Formation of HA-based auto-cross-linking gels via azaide
reactions. 78
 
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