Photocurable GelMA/oxidized pullulan/tannic acid composite hydrogels with antioxidant and antibacterial activities

Bacterial contamination, biofilm formation, and excessive oxidative stress can compromise the performance of conventional wound dressings. In this study, a photocurable composite hydrogel was prepared from gelatin methacryloyl (GelMA), oxidized pullulan (OP), and tannic acid (TA). GelMA provided a photo-crosslinked covalent framework, OP introduced aldehyde groups capable of interacting with residual amino groups in GelMA, and TA supplied polyphenolic groups that contributed noncovalent interactions and biological activity. The chemical modification of GelMA and pullulan was supported by 1H NMR and FTIR spectroscopy. All formulations formed self-supporting hydrogels after 20 s of 365-nm irradiation. Rheological measurements showed elastic-dominant behavior (G′ > Gʺ) over the tested frequency range. The GelMA/OP/TA formulation showed no detectable reduction in L929 cell metabolic activity under the reported test conditions, scavenged 37.0% of DPPH radicals and approximately 90.0% of ABTS radicals, and reduced the survival of methicillin-resistant Staphylococcus aureus and Escherichia coli to below 5.0%. Crystal violet staining further demonstrated a reduction in biofilm biomass. Both protein release and SEM observations indicated a loss of bacterial membrane integrity. These results identify GelMA/OP/TA as a multifunctional photocurable hydrogel with antioxidant and antibacterial potential for further evaluation in wound-related applications.