Facile formation of hydrogels by using functional precursor polymers and the chemoselective Staudinger coupling

Hydrogel formation based on chemoselective crosslinking methods has become an important topic in biomedicine. Although the Staudinger ligation has been utilized in protein modification for many years only one example based on polysaccharides has been published to apply this reaction also for hydrogel formation. Therefore, methacrylate monomers with azide Az-MA or triphenylphosphine TPP-MA functional groups were synthesized and used to prepare two water-soluble precursor copolymers P1 (with Az-MA) and P2 (with TPP-MA) by free radical polymerization. The molecular weight and the composition of the copolymers were analyzed by SEC, H-1 NMR, FTIR and UV/Vis spectroscopy. Mixing of the water-soluble copolymers P1 and P2 in aqueous media led to the irreversible and easy formation of covalently crosslinked polymers. The kinetics of gelation, swelling and mechanical properties of the hydrogels in aqueous PBS buffer can be tuned by the total polymer concentration and the stoichiometric ratio of the complementary functional groups. (C) 2016 Elsevier Ltd. All rights reserved.