Objective

Concerning the importance of developing novel oral hygiene adjuncts, the aim of this study was to screen antibacterial/antibiofilm potential of geraniol and to formulate its stable nanoemulsion(s), capable to combat caries-related streptococcal multispecies biofilm.

Materials and methods

Antibacterial and antibiofilm activities of geraniol were estimated in microdilution and crystal-violet assays, respectively. Five geraniol-based emulsions with Tween80 were formulated and screened for particle size diameter and stability, using dynamic light scattering measurements. The selected emulsion was characterized by TEM, and ex vivo screened against four-species biofilm settled on enamel discs, by determination of CFU.

Results

The antibacterial potential of geraniol was moderate (MICs 0.55–1.11 mg/mL against S. mutans, S. sanguinis, S. gordonii and S. mutans). Geraniol significantly prevented biofilm formation and disrupted pre-formed ones (inhibition ranges against all isolates were 12.00–93.66 %, and 55.54–100 %, respectively). Emulsions (E_ger:tween80) E_200:200, E_500:500, and E_800:800 were stable and nanosized (Zavg˂200 nm). TEM of E_800:800 revealed black spherical spots surrounded by grey stain. Ex vivo four-species streptococcal biofilm disruption assay showed notable inhibitory potential of E_800:800 (ΔLogCFU 1.77 and 3.89, solely and in combination with chlorhexidine, respectively).

Conclusion

E_800:800 showed ex vivo potential against streptococcal multispecies biofilm, especially in combination with chlorhexidine.

Clinical Significance

Presented results encourage further research of the examined nanoemulsions as potential part of daily oral hygiene, aiming to provide prevention of caries development.

中文翻译：

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香叶醇体外和基于香叶醇的乳剂离体对四种链球菌属生物膜的离体潜力与牙科相关

 目的

关于开发新型口腔卫生辅助剂的重要性，本研究的目的是筛选香叶醇的抗菌/抗生物膜潜力，并配制其稳定的纳米乳剂，能够对抗与龋齿相关的链球菌多物种生物膜。

 材料和方法

分别通过微量稀释法和结晶紫法估计香叶醇的抗菌和抗生物膜活性。配制了 5 种含有 Tween80 的香叶醇基乳液，并使用动态光散射测量筛选了粒径和稳定性。通过 TEM 对选定的乳液进行表征，并通过测定 CFU 对沉积在牙釉质盘上的四种生物膜进行离体筛选。

 结果

香叶醇的抗菌潜力中等（MIC 0.55-1.11 mg/mL，针对变异链球菌、血链球菌、戈尔多尼链球菌和变异链球菌）。香叶醇显着阻止生物膜形成并破坏预先形成的生物膜（对所有分离株的抑制范围分别为 12.00-93.66% 和 55.54-100%）。乳剂 （E_{ger：tween80}） E_200：200、E_500：500 和 E_800：800 是稳定的纳米级 （Zavg˂200 nm）。E_800：800 的 TEM 显示被灰色染色包围的黑色球形斑点。离体四种链球菌生物膜破坏试验显示 E_800：800 （ΔLogCFU 1.77 和 3.89，分别单独和与洗必泰联合使用）的显着抑制潜力。

 结论

E_800：800 显示出对链球菌多物种生物膜的离体潜力，尤其是与洗必泰联合使用。

 临床意义

所呈现的结果鼓励进一步研究所检查的纳米乳剂作为日常口腔卫生的潜在组成部分，旨在预防龋齿的发展。