Carbon dots as a new root canal disinfection against Enterococcus faecalis biofilm-induced persistent endodontic infections

Abstract Persistent endodontic infections (PEIs) mediated by bacterial biofilm are the main cause of persistent periapical inflammation, resulting in recurrent periapical abscesses and progressive bone destruction. However, conventional root canal disinfectants are highly damaging to the tooth and periodontal tissue as well as ineffective in treating persistent root canal infections. Antimicrobial materials that are biocompatible with apical tissues and have the ability to eliminate PEIs-associated bacteria are urgently needed. Here, poly(lysine) derived carbon quantum dots (PL-CQDs) are fabricated using a pyrolysis method for removing PEIs-associated bacterial biofilms. Due to their ultra-smaller size, high positive charge, and active reactive oxygen species (ROS) generation capacity, PL-CQDs exhibit highly effective antibacterial activity against Enterococcus faecalis ( E. faecalis ), which is greatly dependent on PL-CQDs concentrations. 100 µg/mL PL-CQDs could totally kill E. faecalis in 5 min. Importantly, PL-CQDs are effective in eliminating biofilms in the isolated teeth model, disrupting the dense structure of biofilms.PL-CQDs have acceptable cytocompatibility and hemocompatibility in vitro as well as good biosafe in vivo . Thus, PL-CQDs provide a new strategy for the treatment of E. faecalis -associated PEIs.