Hamadan University of Medical Sciences Avicenna Journal of Medical Biochemistry 2345-4113 12 2 2024 12 31 Investigating the Antioxidant, Antibacterial, and Anti-biofilm Effects of Cerium Oxide Nanoparticles Synthesized by Alginate 98 105 10.34172/ajmb.2518 EN Soudabe Mousaiyan https://orcid.org/0009-0001-9206-7872 Javad Baharara Ali Es-haghi https://orcid.org/0000-0001-5292-6161 Ehsan Yousefi Journal Article 10.34172/ajmb.2518 2024 07 02 2024 09 08 Background: In recent years, nanoparticles have gained increasing popularity over traditional physicochemical methods for fighting pathogenic microorganisms. Due to their unique properties, cerium oxide nanoparticles (CeO2 NPs) have recently emerged as a promising candidate for biomedical applications. Objectives: This study aimed to investigate the antibacterial effects of CeO2 NPs prepared using alginate, following the disc diffusion method. Methods: For this purpose, four bacterial strains were used in this study: two Gram-positive [Bacillus subtilis (PTCC 1365) and Staphylococcus aureus ATCC 25923] and two Gram-negative [Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 9027]. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were measured using the microdilution method, and the anti-biofilm activity of the synthetic material was also assessed. Results: The results demonstrated the inhibitory effects of the synthesized nanoparticles on gram-positive bacteria, with significant growth inhibition observed in S. aureus and B. subtilis, after exposure to CeO2 NPs. Conclusion: CeO2 NPs synthesized by alginate exhibited significant antibacterial effects against Gram-positive bacteria and could disrupt biofilm structure and prevent further biofilm formation. The findings highlight the potential of CeO2 NPs synthesized by alginate as a novel antibacterial and anti-biofilm therapeutic agent.