Integrative control of mechanical and degradation properties of in situ crosslinkable polyamine-based hydrogels for dual-mode drug release kinetics

Abstract

Michael addition has been extensively utilized in recent years to fabricate hydrogels for biomedical applications, due their ability to undergo reaction under physiological conditions (e.g. neutral pH, mild temperature) to form hydrogels without the need of a catalyst. In this study, mechanical properties and degradation behavior of in situ crosslinkable hydrogels prepared from poly(ethylene glycol) diacrylate (PEGDA) and polyethyleneimine (PEI) are explored. PEGDA with two acrylate groups and PEI with multiple amine groups undergo crosslinking reaction via Michael addition to form hydrogel formation under physiological conditions. Varying the concentrations of PEGDA and PEI, as well as the molecular weight of PEGDA, allow for the control of mechanical properties in a wide range. In addition, these hydrogels are all shown to undergo degradation likely due to the presence of unreacted amine groups on PEI and/or increased local hydroxide content involved with the nucleophilic attack on the ester linkages. With this interesting combination of tunable mechanical properties and degradation, the PEGDA-PEI hydrogel system display a dual-mode drug release kinetics in which the drug release was governed by swelling-controlled and degradation-controlled mechanisms in sequence, which demonstrates the potential of this hydrogel system for drug delivery applications.