Nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate reduce oral bacteria adherence and biofilm formation on human enamel surface

Nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate reduce oral bacteria adherence and biofilm formation on human enamel surface

Objectives: This study investigated the effect of CMC/ACP on oral bacteria adherence and biofilm formation on the enamel surface as well as the underlying mechanism to determine the anti-cariogenic potential of CMC/ACP.Methods: A mineral solution of CMC/ACP was characterised by transmission electron microscope. The bactericidal activity of CMC/ACP was evaluated with the plate count method. An in vitro biofilm model was established on saliva-coated enamel blocks; the effect of CMC/ACP on the adherence of Streptococcus mutans and Streptococcus gordonii to and biofilm formation on these blocks, as well as co-aggregation of Fusobacterium nucleatum was assessed by scanning electron microscopy, crystal violet staining, and confocal microscopy. Bacterial surface charge was estimated with the cytochrome c binding assay and by zeta potential measurement.Results: CMC/ACP nanocomplexes inhibited S. mutans and S. gordonii adherence to enamel blocks by 90% and 86% (P < 0.01), respectively, and biofilm formation by 45% and 44% (P < 0.01), respectively, after 24 h without bactericidal activity. CMC/ACP reduced F. nucleatum attachment to streptococcal biofilm by 75% (P < 0.01) while also altering cytochrome c binding to bacteria and reducing the zeta potential of the bacterial suspension.Conclusions: CMC/ACP nanocomplexes inhibit cariogenic bacterial adherence, co-adhesion, and biofilm formation on the enamel surface, possibly by altering bacterial surface charge and enhancing the flocculation effect. As an agent that promotes remineralisation and has anti-cariogenic effects, CMC/ACP can be used to prevent and treat early caries and white spot lesions.

目的：本研究探讨了羧甲基纤维素/无定形磷酸钙（CMC/ACP）对牙釉质表面口腔细菌黏附和生物膜形成的影响以及潜在机制，以确定CMC/ACP的抗龋潜力。 方法：通过透射电子显微镜对CMC/ACP的矿化溶液进行表征。采用平板计数法评估CMC/ACP的杀菌活性。在唾液包被的牙釉质块上建立体外生物膜模型；通过扫描电子显微镜、结晶紫染色和共聚焦显微镜评估CMC/ACP对变形链球菌和戈登链球菌在这些牙釉质块上的黏附以及生物膜形成的影响，以及对具核梭杆菌共聚集的影响。通过细胞色素c结合试验和ζ电位测量来评估细菌表面电荷。 结果：CMC/ACP纳米复合物在24小时后对变形链球菌和戈登链球菌在牙釉质块上的黏附分别抑制了90%和86%（P < 0.01），对生物膜形成分别抑制了45%和44%（P < 0.01），且无杀菌活性。CMC/ACP使具核梭杆菌对链球菌生物膜的附着减少了75%（P < 0.01），同时也改变了细胞色素c与细菌的结合，并降低了细菌悬液的ζ电位。 结论：CMC/ACP纳米复合物可能通过改变细菌表面电荷和增强絮凝作用，抑制致龋细菌在牙釉质表面的黏附、共黏附和生物膜形成。作为一种促进再矿化且具有抗龋作用的制剂，CMC/ACP可用于预防和治疗早期龋齿和白垩斑病变。