Preparation and swelling properties of “click” hydrogel from polyaspartamide derivatives using tri-arm PEG and PEG-co-poly(amino urethane) azides as crosslinking agents

Copper-assisted azide-alkyne cycloaddition (CuAAC) became a very interesting tool lately for synthesizing biocompatible polymer-based materials such as hydrogels or microgels under mild conditions. As our previous works, modified polyaspartamides with pendent alkyne or azide groups are synthesized by successful ring-opening aminolysis reaction of the polysuccinimide (PSI) using “click” functional amine compounds and ethanolamine. In this work, 3-arm poly(ethylene glycol) (PEG) and 3-arm PEG-co-poly(amino urethane), PEG-(PAU)3, were modified with 3-azido-1-propionic acid (APrA) to obtain the corresponding azido-terminal polymeric crosslinkers, and used to prepare hydrogels with alkynated polyaspartamide via click chemistry. The obtained click hydrogels were transparent and physically strong probably due to highly efficient and homogeneous click reaction. The hydrogel from PEG-(PAU)3 was also pH-sensitive caused by its amino urethane groups in the structure. The hydrogels were characterized by the in-situ gelation and swelling behavior, in vitro cytotoxicity, and morphology. These novel hydrogels have potentials for bioapplications in the fields of drug delivery and tissue engineering.