Construction and characterization of chitosan/poly(acrylamide-[2-(methacryloyloxy)ethyl]trimethylammonium chloride) double-network hydrogel with enhanced antibacterial activity

Antibacterial hydrogels have gained significant attention as appealing materials, but their weak structures largely limit their practical applications. In this study, chitosan (CS)-based double-network antibacterial hydrogels were developed, where polyacrylamide (pAAm) attributed to the high mechanical property and [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MTAC) exerted the strong antibacterial activity, structured as CS/p(AAm-MATC). The structure and morphology of hydrogels with a ratio of pAAm and MTAC of 5:5 were preferred and analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, solid-state NMR spectroscopy, and X-ray diffraction, confirming the successful synthesis. The hydrogels had remarkable compression resistance, withstanding a high strain of 85% with excellent shape recovery. Rheological tests revealed that the samples exhibited characteristic behaviors of hydrogels, with the storage modulus surpassing the loss modulus and increasing with the angular frequency. Furthermore, the composite hydrogels had excellent antibacterial efficacy against Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli) bacteria, mainly attributed to the presence of quaternary ammonium groups in MTAC polymers. These hydrogels, with outstanding mechanical and antibacterial properties, hold promising potential for diverse applications, such as wastewater treatment.

Graphical Abstract

A tough double-network hydrogel is created by a combination of physical and chemical crosslinking methods, exerting high mechanical and enhanced antibacterial properties.