Preparation and properties of antibacterial composite hydrogels based on polyvinyl alcohol, chitosan, and nano-metal oxide

Hydrogels are effective wound dressings because of their capacity to promptly absorb wound exudate and maintain a moist environment for healing. In this work, an antibacterial hydrogel was prepared by freeze–thaw cycling based on polyvinyl alcohol/chitosan/iron–copper–zinc oxide nanocomposite. The hydrogels were characterized using various methods, including Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and field emission scanning electron microscopy. The hydrogels were analyzed for porosity, gel content, water vapour transmission rate, swelling rate, water retention rate, contact angle, and mechanical properties. The effect of the PVA: CS ratio on the mechanical properties and bacterial inhibition zone of hydrogels was particularly analyzed. The antibacterial activity of nano-ZnO, nano copper–zinc, and nano iron copper zinc oxide was qualitatively compared using the zone of inhibition test, and the antibacterial rate of the corresponding hydrogel was quantitatively analyzed using the shake flask method. Cell viability was assayed by using the Cell Counting Kit-8 method, in which NIH3T3 cells were directly incubated together with hydrogel samples to detect the change in cell viability after 24 h. Results indicate that the prepared hydrogels possess excellent biocompatibility, antibacterial rate, porous structure, high swelling rate, and good water retention capacity, making them a potential material for wound dressings.