Mechanisms of Singlet-Oxygen and Superoxide-Ion Generation by Porphyrins and Bacteriochlorins and their Implications in Photodynamic Therapy
Mechanisms of Singlet-Oxygen and Superoxide-Ion Generation by Porphyrins and Bacteriochlorins and their Implications in Photodynamic Therapy
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DOI：
10.1002/chem.201000111
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Arnaut, Luis G.
中科院分区：
文献类型：
--
作者：
Silva, Elsa F. F.;Serpa, Carlos;Arnaut, Luis G.
新的卤化和磺化菌氯及其类似的卟啉被用作单线态氧和超氧离子的光敏剂。阐明了能量和电子转移的机理，并测量了转移速率。电荷转移（CT）络合物的中间作用证明了细菌氯，但排除了卟啉。中间产物的能量和它们相互转化的速率被测量，并被用来获得所有过程的效率。在细菌氯存在下羟基自由基形成的机制被认为涉及光催化步骤。评估了这些光敏剂在癌症光动力治疗（PDT）中的有用性，并给出了以下建议，以设计使用此类光敏剂的更有效的PDT方案：1)当光敏剂与分子氧形成CT配合物时，应在更长的时间内给予光闭，2)如果同时位于同一细胞器中协助体内芬顿反应，Fe2+可以提高光敏剂的效率。
New halogenated and sulfonated bacteriochlorins and their analogous porphyrins are employed as photosensitizers of singlet oxygen and the superoxide ion. The mechanisms of energy and electron transfer are clarified and the rates are measured. The intermediacy of a charge-transfer (CT) complex is proved for bacteriochlorins, but excluded for porphyrins. The energies of the intermediates and the rates of their interconversions are measured, and are used to obtain the efficiencies of all the processes. The mechanism of formation of the hydroxyl radical in the presence of bacteriochlorins is proposed to involve a photocatalytic step. The usefulness of these photosensitizers in the photodynamic therapy (PDT) of cancer is assessed, and the following recommendations are given for the design of more effective PDT protocols employing such photosensitizers: 1) light closes should be given over a more extended period of time when the photosensitizers form CT complexes with molecular oxygen, and 2) Fe2+ may improve the efficiency of such photosensitizers if co-located in the same cell organelle assisting with an in vivo Fenton reaction.