Clinical root canal therapy which takes place through mechanical and chemical strategies is faced with challenges in eliminating bacteria owing to the intricate and curved nature of the root canal system. Moreover, the plaque biofilm within the root canal hinders drug penetration and limits treatment efficacy. Hence, efficient root canal therapy hinges on penetrating into the root canal and overcoming the barriers presented by the plaque biofilms. To penetrate and eradicate biofilms effectively at the root canal, we designed a novel magnetic nanoparticle (MN)-based nanoplatform which was synthesized by the self-polymerization of dopamine on the surface of Fe₃O₄ MNs, and then loaded minocycline through the electrostatic interaction. The therapeutic efficacy of minocycline-loaded magnetic nanoparticles (FDM MNs) under a magnetostatic field was observed by various antibacterial experiments. The synthesized FDM MNs exhibited favorable biocompatibility and robust anti-biofilm efficacy. The designed nanoparticles could effectively navigate biofilms to eradicate bacteria residing deep with the assistance of magnetic force. Furthermore, FDM MNs penetrated into dentin tubules under a magnetic field, effectively disrupting biofilms for deep sterilization. The significant results offered valuable experimental evidence to support the potential clinical utility of magnetic nanoparticles for managing pulpitis and periapical inflammation.

Introduction: Dental caries, a highly prevalent oral disease, significantly compromises oral health. Dental biofilms represent a key etiological factor in caries pathogenesis and pose challenges for eradication due to their protective extracellular matrix. Methods: Herein, we rationally designed a ferro-polydopamine nanozyme (FPN) featuring a flower-like morphology and remarkable peroxidase-like (POD-like) activity. Results: Significantly, FPN efficiently catalyzed low-concentration H ₂ O ₂ under mildly acidic conditions, exhibiting potent antibacterial activity against Streptococcus mutans ( S. mutans ) and robust anti-biofilm efficacy in vitro . Furthermore, enamel disks treated synergistically with FPN and low-dose H2O2 demonstrated significantly inhibited enamel demineralization compared to untreated controls under acidogenic challenge, indicating FPN’s remarkable preventive capacity against early caries. Discussion: Collectively, this study demonstrates that FPN, enabled by its superior POD-like activity and biocompatibility, holds substantial translational potential for significantly reducing clinical H ₂ O ₂ concentrations while effectively preventing early dental caries.