Poly(Lysine)-Derived Carbon Quantum Dots Conquer Enterococcus faecalis Biofilm-Induced Persistent Endodontic Infections

Abstract

Yongzhi Xu,1,2,* Yuanping Hao,2,* Muhammad Arif,3 Xiaodong Xing,4 Xuyang Deng,1 Danyang Wang,1 Yang Meng,2 Shuai Wang,1 Mohamed Sayed Hasanin,5 Wanchun Wang,2 Qihui Zhou3,6 1School of Stomatology, Qingdao University, Qingdao, People’s Republic of China; 2Department of Stomatology, Qingdao Stomatological Hospital Affiliated to Qingdao University, Qingdao, People’s Republic of China; 3Qingdao Key Laboratory of Materials for Tissue Repair and Rehabilitation, School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, People’s Republic of China; 4School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, People’s Republic of China; 5Cellulose and Paper Department, National Research Centre, Dokki, Cairo, Egypt; 6Hubei Key Laboratory of Biomass Fibers and Eco-Dyeing & Finishing, Wuhan Textile University, Wuhan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Wanchun Wang; Qihui Zhou, Email [email protected]; [email protected]: Persistent endodontic infections (PEIs) mediated by bacterial biofilm mainly cause 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 and ineffective in treating persistent root canal infections. Antimicrobial materials that are biocompatible with apical tissues and can eliminate PEIs-associated bacteria are urgently needed.Methods: Here, ϵ-poly (L-lysine) derived carbon quantum dots (PL-CQDs) are fabricated using pyrolysis to remove PEIs-associated bacterial biofilms.Results: Due to their ultra-small 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 kill E. faecalis in 5 min. Importantly, PL-CQDs effectively achieved a reduction of biofilms in the isolated teeth model, disrupting the dense structure of biofilms. PL-CQDs have acceptable cytocompatibility and hemocompatibility in vitro and good biosafety in vivo.Discussion: Thus, PL-CQDs provide a new strategy for treating E. faecalis-associated PEIs. Keywords: carbon quantum dots, Enterococcus faecalis, bacterial biofilm, persistent endodontic infections

Keywords

• carbon quantum dots
• enterococcus faecalis
• bacterial biofilm
• persistent endodontic infections