Mesoporous Calcium-Silicate Nanoparticles Loaded with Prussian Blue Promotes Enterococcus Faecalis Ferroptosis-Like Death by Regulating Bacterial Redox Pathway ROS/GSH

Abstract

Xiao Zhao,1– 3,* Ying Wang,1– 4,* Tingting Zhu,1– 3 Huili Wu,1– 3 Diya Leng,1– 3 Zhiguo Qin,5 Yan Li,6 Daming Wu1– 3 1Department of Endodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, People’s Republic of China; 2Jiangsu Province Key Laboratory of Oral Diseases, Nanjing, People’s Republic of China; 3Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, People’s Republic of China; 4Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, People’s Republic of China; 5Nanjing Medical University, the First Clinical Medical College, Jiangsu Province Hospital, Nanjing, People’s Republic of China; 6State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Daming Wu, Department of Endodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, 1 Shanghai Road, Nanjing, 210029, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]: Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials that have been used to control drug delivery for many years. Ultrasmall Prussian blue nanoparticles (UPBNPs) showed high peroxidase and catalase-like activities. This study evaluated the antibacterial and antibiofilm properties, mechanism and cytotoxicity of UPBNPs-MCSNs composites synthesized by both as precursors.Methods: UPBNPs-MCSNs were prepared and characterized. The antibacterial effect of UPBNPs-MCSNs was evaluated by the MTT assay and CFU counting method, and their biosafety was tested by CCK8. Then explore the antibacterial mechanism, including TEM observation of bacterial morphology, and detection of bacterial ROS, LPO and GSH levels. The antibiofilm activity of UPBNPs-MCSNs was tested by E. faecalis biofilm model in human roots. The roots were pretreated with materials and cultured with E. faecalis, and the survival of E. faecalis on the root canal wall was observed by SEM and CLSM.Results: The results showed that UPBNPs-MCSNs had potent antibacterial and antibiofilm activities. They can aggregate on the dentin surface and significantly inhibit E. faecalis adhesion and colonization. Their antibacterial activity is as effective as NaClO and calcium hydroxide (CH), can significantly prolong the time of bacterial colonization than CH, but have lower cytotoxicity to normal cells. We found that UPBNPs-MCSNs trigger a like classic ferroptosis pathway in bacteria. UPBNPs-MCSNs can induce bacteria to produce ROS and LPO, and reduce GSH level. Moreover, we observed that the metal ions chelator and the antioxidant could block their antibacterial activity.Conclusion: These results reveal that UPBNPS-MCSNs have high antibacterial and antibiofilm, and can mediate the bacterial redox pathway ROS/GSH like the classical pathway of ferroptosis, providing a theoretical basis for them to develop into a safe and effective novel root canal disinfectant.Keywords: antibacterial activity, root canal disinfectant, mesoporous materials, reactive oxygen species, Prussian blue

Keywords

• antibacterial activity
• root canal disinfectant
• mesoporous materials
• reactive oxygen species
• prussian blue