Synthesis of chitosan-PEO hydrogels via mesylation and regioselective Cu(I)-catalyzed cycloaddition

This synthetic approach allowed us to obtain a hydrogel with a controlled crosslinking degree. In fact, the extent of coupling is strictly dependent on the amount of azido groups on chitosan, which in turn can be easily modulated.

In this work, a well-defined hydrogel was developed by coupling chitosan with PEO through "click chemistry". Azide functionalities were introduced onto chitosan, through mesylation of C-6 hydroxyl groups, and reacted with a di-alkyne PEO by a regioselective Cu(I)-catalyzed cycloaddition.