Self-propelled Janus platinum mesoporous-silica nanoparticles for enhanced endodontic treatment

Biofilms contribute to the development of various oral diseases, particularly endodontic infections. The challenges posed by the intricate anatomy of root canals and the resilience of these infections to antimicrobials require innovative treatment strategies to improve endodontic outcomes. This study introduces a novel approach using self-propelled Janus platinum-mesoporous silica nanoparticles (i.e. nanomotors), loaded with chlorhexidine (CHX) and functionalized with a pH-dependent molecular gate bound to a ficin protease, which acts as an enzymatic drill. These multifunctional nanomotors combine unique properties to eliminate biofilms derived from the oral cavity, including H₂O₂-triggered movement, biofilm matrix degradation, and controlled CHX release at acidic pH. The effectiveness of the nanomotors against saliva-derived and root canal biofilms was demonstrated. Notably, H₂O₂-activated nanomotors carrying a low concentration of CHX -ten times lower than conventional commercial formulations- exhibited a strong antimicrobial effect on oral biofilms, whereas CHX alone showed minimal impact. Moreover, the nanomotors disrupted mature Streptococcus mutans biofilms on dentine sections. In addition, the nanodevices effectively penetrated dentinal microtubules, eradicating bacterial biofilms residing within them, thereby underscoring the efficiency of this approach in clinically relevant oral environments. Collectively, these findings suggest that H₂O₂-activated nanomotors loaded with CHX represent a promising treatment strategy for endodontic infections. Their ability to deliver antimicrobial agents in a controlled manner and to reach challenging microenvironments could significantly enhance treatment outcomes of these persistent infections. This approach may serve as an effective complementary therapy in endodontic care, addressing the limitations of current sterilization methods.