Antibacterial and wound healing activities of AgNPs, ZnONPs, and Fe3O4NPs against Acinetobacter baumannii and Escherichia coli.

OBJECTIVES

This study aimed to evaluate the individual and combined effects of silver nanoparticles (AgNPs), zinc oxide nanoparticles (ZnO-NPs), and iron oxide nanoparticles (Fe₃O₄-NPs) on wound healing in a rat model of infection with Acinetobacter baumannii and Escherichia coli, and to compare their efficacy with a standard antibiotic treatment.

RESULTS

AgNPs demonstrated the strongest antibacterial growth inhibition in vitro, while ZnO-NPs showed limited antibacterial activity under the tested conditions. Combination assays indicated enhanced bacterial growth inhibition for AgNP + Fe₃O₄-NPs, whereas ZnO-NPs did not increase antibacterial inhibition in vitro. Nanoparticle-treated wounds showed faster healing than controls in rat models infected with E. coli and A. baumannii. Complete wound closure by day nine was observed in the Ag + ZnO and Fe₃O₄ groups for E. coli infection and in the Ag, ZnO, and Ag + ZnO groups for A. baumannii. Wound-healing rates reached 100% in the Fe₃O₄ and Ag + ZnO groups, which was significantly higher than in untreated controls. Histological evaluation revealed no necrosis in any group, while treated wounds exhibited increased granulation tissue formation and reduced inflammation. Overall, the Ag + ZnO nanoparticle combination showed a synergistic effect, leading to superior antibacterial activity and accelerated wound repair.