Photochemical oxygen consumption sensitized by a porphyrin phosphorescent probe in two model systems
Photochemical oxygen consumption sensitized by a porphyrin phosphorescent probe in two model systems
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DOI：
10.1016/s0006-3495(00)76804-4
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发表时间：
2000-05-01
影响因子：
3.4
通讯作者：
Foster, TH
中科院分区：
文献类型：
--
作者：
Mitra, S;Foster, TH
某些金属卟啉的磷光猝灭被用来测量组织和微血管的pO（2）。金属卟啉三重态的氧猝灭产生单线态氧，单线态氧在生物系统中具有高度反应性，并且这些耗氧反应能够扰乱组织氧合。在体外两个模型体系中，在1.34-134 mW cm（-2）的辐照度范围内，测定了钯卟啉的光化学耗氧动力学。对于一个给定的辐照度，并在不同的卟啉浓度校正后，氧气消耗率是相似的Pd-卟啉结合牛血清白蛋白时，它被肿瘤细胞在球体。在与表面解剖成像中所用的辐照度相当的辐照度下，耗氧率足够低（2.5 μ M·s（-1）），组织氧合最多可减少6%。然而，20 mW cm（-2）的辐照度引发的氧消耗率能够使组织pO（2）降低至少20- 40%。这些测量的消耗率限制了磷光猝灭在厚组织中的应用。还间接测量了钯卟啉的不可逆光漂白。漂白支化比为23 M-1，明显低于卟啉光动力剂。
Phosphorescence quenching of certain metalloporphyrins is used to measure tissue and microvascular pO(2). Oxygen quenching of metalloporphyrin triplet states creates singlet oxygen, which is highly reactive in biological systems, and these oxygen-consuming reactions are capable of perturbing tissue oxygenation. Kinetics of photochemical oxygen consumption were measured for a Pd-porphyrin in two model systems in vitro over a range of irradiances (1.34-134 mW cm(-2)). For a given irradiance, and, after correction for differing porphyrin concentrations, rates of oxygen consumption were similar when the Pd-porphyrin was bound to bovine serum albumin and when it was taken up by tumor cells in spheroids. At irradiances comparable to those used in imaging superficial anatomy, rates of oxygen consumption were sufficiently low (2.5 mu M s(-1)) that tissue oxygenation would be reduced by a maximum of 6%. An irradiance of 20 mW cm(-2), however, initiated a rate of oxygen consumption capable of reducing tissue pO(2) by at least 20-40%. These measured rates of consumption impose limitations on the use of phosphorescence quenching in thick tissues. The irreversible photobleaching of the Pd-porphyrin was also measured indirectly. The bleaching branching ratio, 23 M-1, is significantly lower than that of porphyrin photodynamic agents.