Octahedral Fe3O4 Nanozymes Penetrate and Remove Biofilms on Implants via Photomagnetic Response

Dental implant papilla (DIP) is susceptible to bacterial adhesion and biofilm formation, and oral pathogenic biofilms can cause persistent oral infections. Enrichment of bacterial biofilms on implants can lead to soft tissue irritation and adjacent bone resorption, severely compromising dental health and potentially leading to periodontitis, implant loss and costly follow-up care. Nanozymes (NZs) are recently used in biofilm removal as they can induce the production of reactive oxygen species (ROS), which can kill bacteria. However, the short lifespan of ROS limits their diffusion distance, and affects their therapeutic efficacy. In this study, we prepared Fe3O4 nanoparticles (NZs) with different morphologies: flower-like (F-Fe3O4), hollow spherical (M-Fe3O4), octahedral (O-Fe3O4), and conventional nanoparticles (N-Fe3O4). The ferromagnetic properties of Fe3O4 NZs allow them to move and penetrate the biofilm under the action of a magnetic field. The saturation magnetic intensities of the four samples were as follows: F-Fe3O4 (23.1 emu g−1), M-Fe3O4 (73.34 emu g−1), O-Fe3O4 (96.06 emu g−1), and N-Fe3O4 (52.15 emu g−1). The synergistic combination of photothermal action and catalytic sterilization can effectively remove the biofilm. In addition, the prepared Fe3O4 nanozymes were able to maintain high biological activity on the implant surface with some osteogenic effect.