The utilization of three methylene blue analogues containing hydroxyl functionalized auxochrome units (MBA) and their corresponding novel folic acid esters (FAE) as singlet-oxygen photosensitizers for antimicrobial photodynamic therapy (aPDT) was investigated. A new environmentally friendly ultrasoundassisted procedure for the synthesis of MBA and an optimized protocol for folic acid esterification are reported. Binding of folic acid to MBA did not alter the optical absorption/emission properties of the dyes, the folates exhibiting higher or at least equal fluorescence quantum yields when compared to those of the parent dyes. The photodynamic effect of MBA and FAE was evaluated based on their singlet oxygen generation capacity. The ¹O₂ quantum yields, determined by the indirect detection technique using 1,3-diphenylisobenzofuran (DPBF) as a sensor, appeared to be ∼ 50 % for MBA and decreased to ∼ 20 % in the case of FAE. The antimicrobial efficacy of the new FAE on four bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Deinococcus radiodurans) showed remarkable results especially when combined with photodynamic therapy.

研究了三种含有羟基功能化助色单元（MBA）的亚甲基蓝类似物及其相应的新型叶酸酯（FAE）作为单线态氧光敏剂用于抗菌光动力疗法（aPDT）的应用。报道了一种新的环保超声辅助合成MBA的方法和叶酸酯化的优化方案。叶酸与MBA的结合不会改变染料的光学吸收/发射特性，与母体染料相比，叶酸表现出更高或至少相等的荧光量子产率。根据MBA和FAE的单线态氧生成能力评估其光动力效应。通过使用 1,3-二苯基异苯并呋喃 (DPBF) 作为传感器的间接检测技术确定的¹ O ₂量子产率对于MBA似乎为 ∼ 50%，而对于FAE则下降至 ∼ 20% 。新型FAE对四种细菌菌株（大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌和耐辐射奇球菌）的抗菌功效显示出显着的效果，尤其是与光动力疗法结合使用时。