Guo Wenjing, Li Yang, Wang Siyuan, Wang Yueying, Li Chenhui, Jin Yangye, Li Yuanyuan, Chen Xu, Miao Wenjun
School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing 211816, PR China.
Department of Stomatology, The Fourth Affiliated Hospital of Nanjing Medical University, Nanjing 210011, PR China.
Colloids Surf B Biointerfaces. 2023 May;225:113242. doi: 10.1016/j.colsurfb.2023.113242. Epub 2023 Mar 6.
Dental caries represents one of the most prevalent diseases worldwide, characteristic of the growth of dental plaque and demineralization of tooth enamel. Current medications for eradication of dental plaques and prevention of demineralization suffer from several limitations to overcome, calling for novel strategies with great potency in eliminating cariogenic bacteria and dental plaque that forms, as well as in inhibiting the demineralization of enamel, into an integrated system. Considering the potency of photodynamic therapy in bacteria inactivation and the composition of enamel, we herein report that the novel photodynamic nano hydroxyapatite (nHAP), named Ce6 @QCS/nHAP, was useful for this purpose. Ce6 @QCS/nHAP, comprised of quaternary chitosan (QCS)-coated nHAP loaded with chlorin e6 (Ce6), exhibited good biocompatibility and non-compromised photodynamic activity. In vitro studies revealed that Ce6 @QCS/nHAP could effectively associate with cariogenic Streptococcus mutans (S. mutans), leading to a significant antibacterial effect through photodynamic killing and physical inactivation against the planktonic microbe. Three-dimensional fluorescence imaging suggested that Ce6 @QCS/nHAP exhibited a superior S. mutans biofilm penetration capacity to free Ce6, resulting in effective dental plaque eradiation when light irradiation was applied. The number of surviving bacteria in biofilm was at least 2.8 log units lower in the Ce6 @QCS/nHAP group compared to that in the free Ce6 group. Further, in the S. mutans biofilm-infected artificial tooth model, treatment with Ce6 @QCS/nHAP also resulted in the significant prevention of hydroxyapatite disks from demineralization, with lower percentage of fragmentation and weight loss These data suggest that our photodynamic nanosystem can effectively eradicate dental plaque while also significantly protecting artificial tooth from demineralization, opening up new possibilities in treating bacterium-associated dental caries.
龋齿是全球最普遍的疾病之一，其特征在于牙菌斑的生长和牙釉质的脱矿。目前用于根除牙菌斑和预防脱矿的药物存在若干需要克服的局限性，这就需要有新的策略，能够高效地将消除致龋菌和形成的牙菌斑，以及抑制牙釉质脱矿整合到一个系统中。考虑到光动力疗法在细菌灭活方面的效力以及牙釉质的组成，我们在此报告一种新型的光动力纳米羟基磷灰石（nHAP），即Ce6@QCS/nHAP，可用于此目的。Ce6@QCS/nHAP由负载二氢卟吩e6（Ce6）的季铵化壳聚糖（QCS）包覆的nHAP组成，具有良好的生物相容性且光动力活性不受影响。体外研究表明，Ce6@QCS/nHAP能有效地与致龋变形链球菌（变形链球菌）结合，通过光动力杀伤和对浮游微生物的物理灭活产生显著的抗菌效果。三维荧光成像表明，Ce6@QCS/nHAP对变形链球菌生物膜的穿透能力优于游离的Ce6，光照时可有效消除牙菌斑。与游离Ce6组相比，Ce6@QCS/nHAP组生物膜中存活细菌的数量至少低2.8个对数单位。此外，在变形链球菌生物膜感染的人工牙模型中，用Ce6@QCS/nHAP处理还能显著预防羟基磷灰石盘脱矿，碎片百分比和重量损失更低。这些数据表明，我们的光动力纳米系统能有效消除牙菌斑，同时显著保护人工牙不脱矿，为治疗细菌相关龋齿开辟了新的可能性。
