Antibacterial and anti-inflammatory polyethyleneimine/polyacrylic acid hydrogel loaded with CeO₂ quantum dots for wet tissue wound dressings

Searching for an antibacterial and anti-inflammatory dressing that can stably adhere to wet tissues remains a momentous clinical challenge, especially in the context of treatment failure due to multi-drug-resistant bacteria. Using a hard template method in combination with an in situ chelating strategy, three-dimensional nitrogen-doped graded porous carbon anchored 1.5-2.5 nm CeO2 quantum dots (CeO2-QDs) were tailor-designed in this study. Using the size effect, CeO2-QDs have a higher percentage of Ce3+ and oxygen vacancies that could amplify their antibacterial effects. Polyethyleneimine/polyacrylic acid (PEA) powder could self-gel and be adhesive due to its strong physical interactions, which make it an ideal carrier for CeO2-QDs. PEA@50 (mg/mL) CeO2-QDs hydrogel and PEA@75 (mg/mL) CeO2-QDs hydrogel with moderate doses of CeO2-QDs show a superior antibacterial effect against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains. Furthermore, PEA@50CeO(2)-QDs hydrogels possess excellent anti-inflammatory capacity through their antioxidant activity, which could promote macrophage M2 phenotype polarization. More importantly, cytotoxicity assays on L929 fibroblasts show that PEA@CeO2-QDs hydrogels have no significant toxicity, and a significant proliferative effect could be observed. Overall, PEA@50CeO(2)-QDs hydrogels have the potential to become a multifunctional wet tissue dressing with anti-inflammatory and antiseptic properties to promote the healing of infected wounds.