Physically crosslinked poly(methacrylic acid-co-acrylamide)/gelatin–chitosan (poly-MAGC) interpenetrating polymer network hydrogels for drug delivery and antibacterial activity

Abstract

The pursuit of effective wound healing strategies has driven the development of advanced drug delivery systems that utilize biomaterials to enhance tissue regeneration and control infections. Here we present the synthesis and characterization of a novel interpenetrating polymer network (IPN) hydrogel, comprising poly(methacrylic acid-co-acrylamide)/gelatin–chitosan (poly-MAGC). This hydrogel is designed to be biocompatible, biodegradable, and mechanically robust. Its synthesis was achieved via physically crosslinked thermally induced free radical polymerization using methacrylic acid (MAA) and acrylamide (AAm) as monomers, in combination with gelatin and chitosan, with potassium persulfate (KPS) as the initiator. A thorough characterization was conducted using field emission scanning electron microscopy (FESEM) to analyze morphology and Fourier-transform infrared (FTIR) spectroscopy to confirm the structural composition and chemical identity of functional groups. Drug release experiments were performed with carbenicillin, a hydrophilic antibiotic, as a model therapeutic agent. The poly-MAGC hydrogel exhibited controlled and pH-responsive drug release, whereas the unloaded hydrogel showed no inherent bactericidal activity against E. coli DH5α and E. faecalis. Conversely, carbenicillin-loaded hydrogels revealed significant antibacterial properties against E. coli DH5α. Notably, unlike previously documented acrylic- or chitosan-based hydrogels, poly-MAGC uniquely combines both synthetic (MAA, AAm) and natural (gelatin, chitosan) polymers through physical crosslinking, avoiding toxic chemical crosslinkers, and achieving a high drug loading efficiency of 89%, enhanced pH-responsive swelling, and remarkable mechanical stability. This synergistic design presents clear advantages over traditional PAA/PMAA or gelatin-only systems, which frequently experience issues with stability or uncontrolled release. Overall, these results position poly-MAGC as a promising multifunctional material for wound dressing, facilitating controlled drug delivery and effective healing.