Amino-yne Reaction for the Synthesis of Degradable Hydrogels: Study of the Cleavage of β-Aminoacrylate Cross-Links

This work addresses a study of PEG-derived hydrogels based on β-aminoacrylate cross-links and obtained by amino-yne click chemistry, using a β-aminoacrylate-based model molecule as reference. The pH-triggered cleavage of the β-aminoacrylate bonds was monitored confirming not only the release of the conjugated amine but also the formation of a mixture of chemical species that depends on the acidity of the medium. Moreover, overall hydrogel degradation rates were able to be adjusted by modifying pH, temperature, polymer concentration, or the amine selected as linker of PEG chains. In particular, the labile nature of the β-aminoacrylate bond was confirmed even under physiological conditions (pH 7.4, 37 °C), leading to long-term material degradation. The release and recovery of the conjugated amine after the cleavage of the β-aminoacrylate bonds was demonstrated at both acidic and physiological pH, mimicking the results acquired through model molecule studies.