Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, 259, Wen-Hwa First Road, Kwei-Shan, Tao-Yuan 333, Taiwan.
Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, 259, Wen-Hwa First Road, Kwei-Shan, Tao-Yuan 333, Taiwan; Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, 261, Wen-Hwa First Road, Taoyuan, Taiwan; Department of Chemical Engineering, Ming Chi University of Technology, 84, Gung-Juan Road, New Taipei City, Taiwan; Department of Ophthalmology, Chang Gung Memorial Hospital, 5, Fu-Hsing Street, Taoyuan, Taiwan.
Photodiagnosis Photodyn Ther. 2018 Mar;21:190-200. doi: 10.1016/j.pdpdt.2017.12.007. Epub 2017 Dec 13.
Photodynamic therapy has been studied as a method for inactivating bacterial growth. Workers have used planktonic bacterial as well as biofilm bacterial cultures to evaluate the potential of photodynamic therapy in inactivating bacteria. However, almost all the studies use a photosensitiser in aqueous solution, which could be detrimental to the efficiency of photodynamic therapy.
In this study, the photodynamic killing effect of toluidine blue O (TBO) has been investigated on Staphylococcal biofilms in-vitro. The sensitivity of the in-vitro biofilms to photodynamic killing action was compared using different formulations of TBO, different dosages of photosensitiser and different light irradiation strengths. Effect of TBO formulations on bacterial quorum sensing system was evaluated using a colorimetric assay. Finally, dual staining using hoechst and propidium iodide stains was carried out on the photodynamically treated biofilms to visualise and compare the effects of photodynamic therapy. Scanning electron microscope imagery was also carried out to evaluate the photodynamic killing effect on the in-vitro biofilms.
The sensitivity of biofilms to the photodynamic killing effect increased proportionally with the photosensitiser dosage and the light irradiation duration. TBO encapsulated in microemulsion was more effective in killing the biofilm bacteria than only TBO in water. The combination of TBO in microemulsion with EDTA was another effective way of increasing the photodynamic killing effect on the bacterial biofilms. Effect of encapsulated TBO on the quorum sensing system of bacteria was greater than the effect of aqueous solution of TBO. The in-vitro Staphylococcal biofilms could thus be inhibited by the photodynamic effect, and TBO encapsulated in microemulsion was much more effective than only TBO in water.
The encapsulation of a photosensitiser is an effective way of increasing the likelihood of the complete and successful inactivation of the biofilm growth. The encapsulated photosensitiser achieves higher inactivation of the bacterial biofilm than that of the aqueous solution of a photosensitiser.
光动力疗法已被研究用于灭活细菌生长。研究人员使用浮游细菌和生物膜细菌培养物来评估光动力疗法灭活细菌的潜力。然而，几乎所有的研究都使用水溶性的光敏剂，这可能会降低光动力疗法的效率。
本研究采用甲苯胺蓝 O（TBO）研究了金黄色葡萄球菌生物膜的体外光动力杀伤效应。通过比较不同 TBO 配方、不同光敏剂剂量和不同光照强度，比较了体外生物膜对光动力杀伤作用的敏感性。使用比色法评估 TBO 配方对细菌群体感应系统的影响。最后，对光动力处理后的生物膜进行 hoechst 和碘化丙啶双重染色，以可视化和比较光动力疗法的效果。还进行了扫描电子显微镜成像，以评估光动力对体外生物膜的杀伤效果。
生物膜对光动力杀伤效应的敏感性与光敏剂剂量和光照时间成正比增加。包封在微乳液中的 TBO 比仅在水中的 TBO 更有效地杀死生物膜细菌。TBO 微乳液与 EDTA 的组合是另一种增加细菌生物膜光动力杀伤效果的有效方法。包封的 TBO 对细菌群体感应系统的影响大于 TBO 水溶液的影响。因此，体外金黄色葡萄球菌生物膜可以被光动力效应抑制，并且包封在微乳液中的 TBO 比仅在水中的 TBO 更有效。
光敏剂的包封是增加完全和成功灭活生物膜生长的可能性的有效方法。包封的光敏剂比光敏剂的水溶液更有效地灭活细菌生物膜。
