Chitosan-based dihydromyricetin composite hydrogel demonstrating sustained release and exceptional antibacterial activity

Plant-derived antibacterial agents are increasingly pivotal in mitigating the escalating threat posed by pathogenic microorganisms. Dihydromyricetin (DMY), a plant bioactive compound prevalent in Ampelopsis grossedentata, exhibits remarkable antibacterial properties. However, its poor solubility in water significantly hinders its application in antibacterial therapies, necessitating the exploration of suitable carriers for the loading and sustained release of DMY. In this study, a chitosan-based hydrogel was rapidly synthesized at 25 °C using carboxymethyl chitosan and sodium alginate as precursors, and then utilized for the encapsulation of DMY. The as-prepared hydrogel was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis, indicating its favorable swelling properties, injectability, transparency, and self-healing capabilities. Antibacterial assays demonstrated that both surface and internal of the hydrogel exhibited over 99 % inhibition against both Pseudomonas aeruginosa and Staphylococcus aureus when the DMY loading concentration reached 0.4 mg/mL. Furthermore, drug release studies demonstrated that the hydrogel effectively sustained the release of DMY for up to 130 h, irrespective of the acidic or alkaline aqueous solutions, as well as in phosphate-buffered saline. These findings provide novel insights and references for the synergistic antibacterial application of plant-derived agents in conjunction with hydrogels.