Abstract：
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.
摘要：
龋齿是全世界最普遍的疾病之一，牙菌斑生长和牙釉质脱矿的特征。目前用于根除牙菌斑和预防脱矿质的药物存在一些需要克服的局限性。呼吁在消除形成的致龋细菌和牙菌斑方面具有巨大效力的新策略，以及抑制牙釉质的脱矿质，成为一个综合的系统。考虑到光动力疗法在细菌灭活中的效力和牙釉质的组成，我们在这里报道了新型光动力纳米羟基磷灰石(nHAP)，名为Ce6@QCS/nHAP,对这个目的是有用的。Ce6@QCS/nHAP,由负载有氯酸e6（Ce6）的季壳聚糖（QCS）涂覆的nHAP组成，表现出良好的生物相容性和不损害的光动力活性。体外研究表明，Ce6@QCS/nHAP可以有效地与致龋变形链球菌（S.mutans)，通过对浮游微生物的光动力杀死和物理灭活，从而产生显着的抗菌作用。三维荧光成像表明，Ce6@QCS/nHAP表现出优于游离Ce6的变形链球菌生物膜渗透能力，从而在施加光照射时产生有效的牙菌斑辐射。与游离Ce6组相比，Ce6@QCS/nHAP组的生物膜中存活细菌的数量至少低2.8log单位。Further,在变形链球菌生物膜感染的人造牙齿模型中，用Ce6@QCS/nHAP处理也显著防止了羟基磷灰石圆盘的脱矿质，这些数据表明，我们的光动力纳米系统可以有效地根除牙菌斑，同时还可以显着保护人造牙齿免受脱矿质，开辟了治疗细菌相关龋齿的新可能性。
