Data_Sheet_1_An Insight Into the Potentiation Effect of Potassium Iodide on aPDT Efficacy.docx

Antimicrobial photodynamic therapy (aPDT) is gaining a special importance as an effective approach against multidrug-resistant strains responsible of fatal infections. The addition of potassium iodide (KI), a non-toxic salt, is recognized to increase the aPDT efficiency of some photosensitizers (PSs) on a broad-spectrum of microorganisms. As the reported cases only refer positive aPDT potentiation results, in this work we selected a broad range of porphyrinic and non-porphyrinic PSs in order to gain a more comprehensive knowledge about this aPDT potentiation by KI. For this evaluation were selected a series of meso-tetraarylporphyrins positively charged at meso positions or at β-pyrrolic positions and the non-porphyrinic dyes Methylene blue, Rose Bengal, Toluidine Blue O, Malachite Green and Crystal Violet; the assays were performed using a bioluminescent E. coli strain as a model. The results indicate that KI has also the ability to potentiate the aPDT process mediated by some of the cationic PSs [Tri-Py(+)-Me, Tetra-Py(+)-Me, Form, RB, MB, Mono-Py(+)-Me, β-ImiPhTPP, β-ImiPyTPP, and β-BrImiPyTPP] allowing a drastic reduction of the treatment time as well as of the PS concentration. However, the efficacy of some porphyrinic and non-porphyrinic PSs [Di-Py(+)-Me opp, Di-Py(+)-Me adj, Tetra-Py, TBO, CV, and MG] was not improved by the presence of the coadjuvant. For the PSs tested in this study, the ones capable to decompose the peroxyiodide into iodine (easily detectable by spectroscopy or by the visual appearance of a blue color in the presence of amylose) were the most promising ones to be used in combination with KI. Although these studies confirmed that the generation of 1O2 is an important fact in this process, the PS structure (charge number and charge position), aggregation behavior and affinity for the cell membrane are also important features to be taken in account.

抗菌光动力疗法（Antimicrobial photodynamic therapy, aPDT）作为一种对抗引发致命感染的多重耐药菌株的有效手段，正受到日益广泛的关注。无毒盐类碘化钾（potassium iodide, KI）的添加，已被证实可提升部分光敏剂（photosensitizers, PSs）对广谱微生物的aPDT效能。由于已有报道仅提及aPDT的增效阳性结果，本研究选取了涵盖卟啉类与非卟啉类的广谱光敏剂，以期更全面地阐明KI对aPDT的增效作用。本次评估选取了一系列在中位或β-吡咯位带正电荷的中位四芳基卟啉，以及非卟啉类染料亚甲蓝（Methylene blue, MB）、孟加拉玫瑰红（Rose Bengal, RB）、甲苯胺蓝O（Toluidine Blue O, TBO）、孔雀石绿（Malachite Green, MG）与结晶紫（Crystal Violet, CV）；实验以生物发光大肠杆菌菌株为模型开展。结果显示，KI同样可增强部分阳离子光敏剂[三吡啶鎓甲基（Tri-Py(+)-Me）、四吡啶鎓甲基（Tetra-Py(+)-Me）、Form、RB、MB、单吡啶鎓甲基（Mono-Py(+)-Me）、β-咪唑基苯基四苯基卟啉（β-ImiPhTPP）、β-咪唑基吡啶四苯基卟啉（β-ImiPyTPP）以及β-溴代咪唑基吡啶四苯基卟啉（β-BrImiPyTPP）]介导的aPDT过程，可大幅缩短治疗时长并降低光敏剂使用浓度。然而，部分卟啉类与非卟啉类光敏剂[二吡啶鎓甲基邻位异构体（Di-Py(+)-Me opp）、二吡啶鎓甲基间位异构体（Di-Py(+)-Me adj）、四吡啶卟啉（Tetra-Py）、甲苯胺蓝O（TBO）、结晶紫（CV）以及孔雀石绿（MG）]的效能并未因该辅剂的添加而得到提升。针对本研究中测试的光敏剂而言，能够将过碘化物分解为碘（可通过光谱法或直链淀粉存在时的蓝色视觉显色现象轻松检测）的光敏剂，是与KI联合使用的最具应用前景的候选者。尽管本研究证实单线态氧（1O2）的生成是该过程中的重要环节，但光敏剂的结构（电荷数与电荷位置）、聚集行为以及对细胞膜的亲和力同样是需要考量的关键特征。