MECHANISMS OF SINGLET OXYGEN-DEPENDENT PHOTOSENSITIVITY

当光与内源性或外源性的光相互作用时， 皮肤和眼睛中的外源性化学物质。 这个过程可以产生 不良临床后果，如光毒性和光过敏; 或者它可以具有有益的效果，如在肿瘤光动力疗法（PDT）中， 和煤焦油或松脂（PUVA）疗法来治疗银屑病。 光敏化是由光诱导产生的游离的 自由基和/或单线态氧（1 O2），最低电子激发态 分子氧。 因为后一个物种可能在这两个方面都很重要 光毒性反应和PDT，我们已经开发出最先进的 能检测特征磷光的仪器 在1268 nm处为1 O2。 这种仪器使我们能够描绘出 光敏剂产生1 O2的物理过程 包括吩噻嗪、四环素、苯并恶唑合成染料， 蒽林和1，8-二羟基蒽醌。 单线态氧一直是 与苯并蒽酮（7 H-苯并[de]蒽-7-基）的光毒性有关。 1），一种由1，8-二羟基蒽醌制备的染料中间体。 潜在的光动力剂1，5-二氨基-4，8-二甲氧基-蒽醌和 相关化合物被证明是有效的1 O2发生器， 解释它们对培养的人类白血病细胞的细胞毒性。 的 研究了阳离子表面活性剂对 已经在水溶液和水溶液中研究了增感剂曙红和玫瑰红。 有机溶剂 纳秒激光闪光光解光谱仪 已建成并成功测试。 这些设备现在允许我们 进行时间分辨瞬态吸收和发射光谱 光敏剂的激发态中间体（1 O2的前体）。 该光谱仪正在进行修改，以测量单线态氧的寿命 在有机溶剂和生物系统中。

Photosensitization can result when light interacts with endogenous or exogenous chemical agents in the skin and eyes. This process can produce undesirable clinical consequences, as in phototoxicity and photoallergy; or it can have beneficial effects, as in tumor photodynamic therapy (PDT) and coal-tar or psoralen (PUVA) therapy against psoriasis. Photosensitization results from the light-induced production of free radicals and/or singlet oxygen (1O2), the lowest electronic excited state of molecular oxygen. Because the latter species may be important in both phototoxic reactions and PDT, we have developed state-of-the-art instrumentation capable of detecting the characteristic phosphorescence of 1O2 at 1268 nm. This instrumentation has permitted us to delineate the photophysics of 1O2 production from a number of photosensitizers including phenothiazines, tetracycline, benzoxazoles synthetic dyes, anthralin and 1,8-dihydroxy-anthraquinone. Singlet oxygen has been implicated in the phototoxicity of benzanthrone (7H-benz[de]anthracene-7- one), a dye intermediate prepared from 1,8-dihydroxyanthraquinone. Potential photodynamic agent 1,5-diamino-4,8-dimethoxy-anthraquinone and related compounds were shown to be efficient 1O2 generators which may explain their cytotoxicity to human leukemic cells in culture. The influence of cationic surfactants on the photoprocesses of the sensitizers eosin and rose bengal have been studied in both aqueous and organic solvents. A nano-second laser flash photolysis spectrometer has been built and successfully tested. This equipment now permits us to carry out time-resolved transient absorption and emission spectroscopy on excited state intermediates (precursors to 1O2) of photosensitizers. The spectrometer is being modified to measure singlet oxygen lifetimes in organic solvents and biological systems.