Résumé : Biofilm infections pose a rising threat to public health due to its existing protective shield, which preventing biocide penetration. Here, the oleate-capped iron oxide nanoparticles (OIONPs) were synthesized by the high-temperature method first; after then, the poly(acrylic acid)-capped iron oxide nanoparticles (PIONPs) were obtained via a ligand exchange reaction between OIONPs and sodium poly(acrylic acid). The physicochemical properties of PIONPs were evaluated by Fourier-transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Transmission Electron Microscopy (STEM), Dynamic Light Scattering (DLS), and zeta potential. The FT-IR analysis confirmed the successful ligand exchange on the surface of iron oxide nanoparticles. STEM images displayed that the prepared PIONPs were monodisperse spherical nanoparticles. The PIONPs were stable in ultrapure water and could be kept for 5 weeks without aggregation. Next, Cell Counting Kit-8 (CCK-8) assay and fluorescent images confirmed the excellent cytocompatibility of PIONPs, while the iron concentration of PIONPs was in the range of 5∼120 mg/L. Finally, PIONPs exhibited efficient antibacterial activity against E. coli and S. aureus, and Staphylococcus aureus subsp. aureus Rosenbach (SASAR) biofilm could be destroyed by treating PIONPs under alternating current (AC) applied field conditions.