Antibacterial and Antibiofilm Activity of Iron Oxide Nanoparticles: An Integrative Systematic Review

Background/Objectives: The global rise in antimicrobial resistance has intensified the search for alternative therapeutic strategies capable of overcoming bacterial tolerance and biofilm-associated infections. Iron oxide nanoparticles (IONPs) have emerged as promising candidates due to their physicochemical properties and potential multimodal mechanisms of action. This integrative review aimed to evaluate the antibacterial and antibiofilm activity of iron oxide nanoparticles against Gram-positive and Gram-negative bacteria, as well as their potential synergistic effects with conventional antibiotics. Methods: A structured search was conducted in PubMed, Web of Science, BVS, LILACS, and Redalyc databases using predefined descriptors related to iron nanoparticles and bacterial inhibition. Fifteen studies published between 2014 and 2024 met the inclusion criteria. The methodological quality of the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist. Most studies presented low to moderate risk of bias and the findings were categorized into three thematic areas: antibacterial activity of IONPs, synergistic interaction with antibiotics, and reported adverse effects. Results: Overall, IONPs demonstrated inhibitory effects against clinically relevant pathogens, including Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, showing activity against both planktonic cells and biofilm formation. Synergistic effects with antibiotics were frequently reported, suggesting enhanced antimicrobial efficacy potentially mediated by increased membrane permeability and reactive oxygen species generation. Conclusions: Iron oxide nanoparticles show promising antibacterial and antibiofilm effects and may act as adjuncts to conventional antibiotics. Nevertheless, further standardized and translational studies are required before clinical implementation.