PVA/Poly(hexamethylene guanidine)/Gallic Acid Composite Hydrogel Films and Their Antibacterial Performance
Xu Yang, Baolong Wang, Di Sha, Yonggang Liu, Zhi Liu, Kai Shi, Wei Liu, Cong Yu, Xiangling Ji
Abstract
Carboxylated poly(vinyl alcohol) (PVA-COOH) is prepared by modifying PVA with succinic anhydride. Then, poly(hexamethylene guanidine (PHMG) as a cross-linker and gallic acid (GA) as an antioxidant are added to obtain PVA-based composite hydrogel films (PVA-COOH-PHMG/GA). The as-prepared PVA-based composite films show hydrophilic surfaces, high swelling ratios of 600–700%, low water solubility for PVA-COOH-PHMG samples (about 10%), and good mechanical properties. Importantly, when the initial bacterial concentration is 107 CFU/mL, the antibacterial rate of PVA-based composite films against Escherichia coli and Staphylococcus aureus can reach 99.999%. When the initial bacterial concentration is 108 CFU/mL, the antibacterial rates of these composite films against E. coli and S. aureus can be 99.9999% and 99.988%, respectively. The antibacterial mechanism is also discussed via a live/dead bacteria assay. The cytotoxicity test reveals that the resultant PVA-COOH-PHMG composite hydrogel films without GA have good biocompatibility toward L929 cells, but PVA-COOH-PHMG/GA composite films with addition of GA decrease the cell viability. Interestingly, the PVA-COOH-PHMG/GA composite hydrogel films can scavenge 70% of 1,1-diphenyl-2-picryhydrazyl (DPPH) free radical because of the release of GA, indicating an excellent antioxidant efficiency. It is anticipated that the resultant PVA-based composite hydrogel films with an adequate amount of GA not only possess excellent antibacterial properties but also exhibit a good antioxidant activity. Therefore, they show potential for biomedical field applications as wound dressings.