Self-Propelled MnO₂-Based Colloidal Motors for Active Treatment of Periodontal Inflammation

Chemically powered colloidal motors exhibit significant potential for applications in oral cleaning and antimicrobial treatment. The integration of MnO₂-based colloidal motors with common mouth-rinsing H₂O₂ solutions for sterilization and disinfection via reactive oxygen species (ROS) represents an ideal approach. In this study, we fabricate uniform dumbbell-shaped (DS-MnO₂-motor), spherical (S-MnO₂-motor), and silver half-coated spherical Janus Ag-MnO₂ colloidal motors (JS-MnO₂-motor) using hydrothermal, co-precipitation, and sputtering methods, respectively. These motors are propelled by O₂ bubble ejection generated from the catalytic decomposition of low-concentration H₂O₂ by peroxidase-like MnO₂ components. Notably, the JS-MnO₂-motors achieve a maximum speed of 146.4 µm s^-1 in gargle containing 1.5% H₂O₂. In vitro and in vivo antimicrobial trials demonstrated that the JS-MnO₂-motor gargle exhibits superior sterilization rates of 98.1% and 97.4% against both planktonic and biofilm-forming P. gingivalis and F. nucleatum. Consequently, it significantly enhances the therapeutic efficacy in treating periodontitis in Wistar rats, as evidenced by a marked reduction in inflammatory cells. The mechanical force exerted by these colloidal motors, along with cation adhesion to bacterial membranes and the antimicrobial effects of ROS, collectively contribute to this enhanced performance. Our findings introduce a novel strategy for the treatment of chronic inflammatory diseases.