Prochnow Emilia Pithan, Martins Maritieli Righi, Campagnolo Cibele Bruno, Santos Roberto Christ, Villetti Marcos Antonio, Kantorski Karla Zanini
Graduate Program in Oral Science, Periodontology Unit, School of Dentistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil.
Graduate Program in Nanoscience, Franciscan University Center, Santa Maria, Rio Grande do Sul, Brazil.
Photodiagnosis Photodyn Ther. 2016 Mar;13:291-296. doi: 10.1016/j.pdpdt.2015.08.008. Epub 2015 Aug 24.
Methylene blue (MB) and toluidine blue (TB) are recognized as safe photosensitizers (Ps) for use in humans. The clinical effectiveness of the antimicrobial photodynamic therapy with MB and TB needs to be optimized, and ethanol can increase their antimicrobial effect. Formulations of MB and TB containing ethanol were evaluated for their ability to produce singlet oxygen and their antibacterial effect on Pseudomonas aeruginosa biofilms.
Photoactivated formulations were prepared by diluting the Ps (250 μM) in buffered water (pH 5.6, sodium acetate/acetic acid), 10% ethanol (buffer: ethanol, 90:10), or 20% ethanol (buffer: ethanol, 80:20). Biofilms also were exposed to the buffer, 10% ethanol, or 20% ethanol without photoactivation. Untreated biofilm was considered the control group. The production of singlet oxygen in the formulations was measured based on the photo-oxidation of 1,3-diphenylisobenzofuran. The photo-oxidation and CFU (log10) data were evaluated by two-way ANOVA and post-hoc Tukey's tests.
In all the formulations, compared to TB, MB showed higher production of singlet oxygen. In the absence of photoactivation, neither the buffer nor the 10% ethanol solution showed any antimicrobial effect, while the 20% ethanol solution significantly reduced bacterial viability (P=0.009). With photoactivation, only the formulations containing MB and both 10% and 20% ethanol solutions significantly reduced the viability of P. aeruginosa biofilms when compared with the control.
MB formulations containing ethanol enhanced the antimicrobial effect of the photodynamic therapy against P. aeruginosa biofilms in vitro.
亚甲蓝（MB）和甲苯胺蓝（TB）被公认为可用于人类的安全光敏剂。亚甲蓝和甲苯胺蓝抗菌光动力疗法的临床效果需要优化，乙醇可增强它们的抗菌效果。对含乙醇的亚甲蓝和甲苯胺蓝制剂产生单线态氧的能力及其对铜绿假单胞菌生物膜的抗菌作用进行了评估。
通过将光敏剂（250 μM）稀释于缓冲水（pH 5.6，醋酸钠/醋酸）、10%乙醇（缓冲液：乙醇，90:10）或20%乙醇（缓冲液：乙醇，80:20）中来制备光活化制剂。生物膜也暴露于未进行光活化的缓冲液、10%乙醇或20%乙醇中。未处理的生物膜被视为对照组。基于1,3 - 二苯基异苯并呋喃的光氧化来测量制剂中单线态氧的产生。通过双向方差分析和事后Tukey检验对光氧化和CFU（log10）数据进行评估。
在所有制剂中，与甲苯胺蓝相比，亚甲蓝产生的单线态氧更多。在没有光活化的情况下，缓冲液和10%乙醇溶液均未显示出任何抗菌作用，而20%乙醇溶液显著降低了细菌活力（P = 0.009）。进行光活化后，与对照组相比，仅含亚甲蓝以及10%和20%乙醇溶液的制剂显著降低了铜绿假单胞菌生物膜的活力。
含乙醇的亚甲蓝制剂在体外增强了光动力疗法对铜绿假单胞菌生物膜的抗菌作用。
