Molecular Physical Chemistry Center, and IN-Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
Int J Mol Sci. 2013 Sep 9;14(9):18557-71. doi: 10.3390/ijms140918557.
The present study investigates the photochemical properties of potential photosensitizers for photodynamic therapy, namely four commercial heptamethinecyanine dyes (IR125, IR780, IR813, IR820). Spectroscopic studies were made by means of laser induced fluorescence and laser flash photolysis in order to obtain fluorescence quantum yields and transient absorption spectra. Fluorescence lifetimes were also determined. The differences encountered were essentially related with the interaction of the sulfonate groups with the solvent, and also regarding the rigidification of the central bridge connecting the two nitrogen-containing heterocyclic groups. Transient absorption studies were performed both in aerated and oxygen free samples, to conclude about the formation of photoisomers and triplet state. For the four dyes under study, a cytotoxic evaluation in the dark and after irradiation was performed using HeLa cells as the model cell line, which revealed significant changes after irradiation mainly in IR125 and IR813 dyes. Confocal microscopy analysis showed that these dyes tend to enter to the intracellular space.
本研究调查了光动力治疗潜在光敏剂的光化学性质，即四种商业七甲川花菁染料（IR125、IR780、IR813、IR820）。通过激光诱导荧光和激光闪光光解进行了光谱研究，以获得荧光量子产率和瞬态吸收光谱。还测定了荧光寿命。遇到的差异主要与磺酸盐基团与溶剂的相互作用有关，以及与连接两个含氮杂环基团的中央桥的刚性化有关。在有氧和无氧样品中进行了瞬态吸收研究，以得出关于光异构体和三重态形成的结论。对于所研究的四种染料，在黑暗中和照射后使用 HeLa 细胞作为模型细胞系进行了细胞毒性评估，结果表明主要在 IR125 和 IR813 染料照射后发生了明显变化。共聚焦显微镜分析表明，这些染料倾向于进入细胞内空间。
