Rhodamine (R) compounds are photosensitizers with low production of ¹O₂, so these compounds have not been considered very often for photodynamic therapy (PDT). Rhodamine-6G (R6G) undergoes electron transfer reactions with folic acid (FA). This reaction converts this form of R into a potential photosensitizer (PS) for PDT. The occurrence of this reaction with other R or oxygen has not yet been proven. The low penetrability of visible light into the skin has led to the proposal of a PDT light source alternative to Cerenkov radiation (CR). This work evaluates and compares the occurrence of type-I transfer reactions of R6G, R123, and RB with FA and oxygen when irradiated at 532 nm. The potential use of these compounds as type-I photosensitizers for PDT was also evaluated in vitro by excitation with CR. R electron transfer reactions with FA and oxygen were monitored by emission fluorescence and ultraviolet/visible (UV/Vis) absorption of 2,6-dichlorophenol-indophenol (DCPIP) as a redox indicator, respectively. ¹⁷⁷Lu and ¹⁸F were used as CR sources. The results showed that the three R compounds underwent type-I transfer reactions with FA in the order R123 > R6G > RB when irradiated at 532 nm. Excitation of R6G using CR was demonstrated. Only R6G showed a type-I reaction with O₂. By irradiating T47D tumor cells with a 532 nm laser light, cell death occurred in the order R6G>R123>RB. The same trend was found when cells were irradiated with CR. The possibility of using the type-I reaction between R compounds and biomolecules provides a new perspective in the use of these dyes in PDT.

罗丹明（R）的化合物是具有低生产光敏剂¹ Ò ₂，所以这些化合物还没有被认为是非常经常用于光动力疗法（PDT）。罗丹明6G（R6G）与叶酸（FA）进行电子转移反应。该反应将这种形式的R转化为潜在的PDT光敏剂（PS）。与其他R或氧的反应尚未得到证实。可见光对皮肤的低渗透性导致提出了替代切伦科夫辐射（CR）的PDT光源的建议。这项工作评估并比较了在532 nm辐射时，R6G，R123和RB与FA和氧气发生的I型转移反应。还评估了这些化合物作为PDT的I型光敏剂的潜在用途在体外用CR激发。与FA和氧的R电子转移反应分别通过发射荧光和作为氧化还原指示剂的2,6-二氯苯酚-吲哚酚（DCPIP）的紫外/可见光（UV / Vis）吸收进行监测。¹⁷⁷ Lu和¹⁸ F被用作CR源。结果表明，当在532 nm处照射时，三种R化合物与FA进行I型转移反应，顺序为R123> R6G> RB。证明了使用CR激发R6G。只有R6G与O ₂表现出I型反应。通过用532nm激光照射T47D肿瘤细胞，以R6G＞ R123＞ RB的顺序发生细胞死亡。当用CR照射细胞时，发现了相同的趋势。在R化合物和生物分子之间使用I型反应的可能性为在PDT中使用这些染料提供了新的视角。