Shape memory polyacrylamide/gelatin hydrogel with controllable mechanical and drug release properties potential for wound dressing application

In this work, various shape memory polyacrylamide/gelatin (PAM-Gels) hydrogels with interpenetrating double networks were synthesized via a facile one-pot method. Taking advantage of the thermal reversible property of physical gelatin network and the constant of chemical crosslinking polyacrylamide network, the prepared PAMGels hydrogels showed shape memory function under warm water. Moreover, the shape memory, mechanical, drug release, and swelling properties of the prepared PAM-Gels hydrogels could be tuned by altering the gelatin component content. Notably, the PAM-Gel5 hydrogel containing 5% w/v of gelatin exhibited the most effective enhancements in physicochemical properties, and the highest shape fixity and shape recovery rate were 78.2% and 93.5%, respectively. Meanwhile, it could retain the integrity of its shape even with high water uptake. More importantly, the PAM-Gel5 hydrogel possessed well balanced mechanical properties (e.g. tensile strength was 0.57 MPa and elongation at break was 1556% in tensile test; compression stress was 0.06 MPa and Young's modulus was 0.38 MPa in compression test) among the as-prepared PAM-Gels hydrogels, due to its uniform pore size distribution and smaller pore size. Furthermore, the drug release experiment revealed that the PAM-Gel5 hydrogel showed sustained release characteristics, and the majority of loaded model drug could be released within 24 h under physiological conditions. Additionally, cytotoxicity test suggested the representative PAMGel5 hydrogel exhibited good in vitro cytocompatibility. This work provides a viable avenue for developing bio-compatible shape memory hydrogel with acceptable mechanical and drug release properties applied as wound dressing.