Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants,Journal of the American Chemical Society

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Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2009-01-14 , DOI: 10.1021/ja807484b
Marina K. Kuimova ₁ , Gokhan Yahioglu ₁ , Peter R. Ogilby ₁

Affiliation

Singlet molecular oxygen, O(2)(a(1)Delta(g)), can be created in a single cell from ground-state oxygen, O(2)(X(3)Sigma(g)(-)), upon focused laser irradiation of an intracellular sensitizer. This cytotoxic species can subsequently be detected by its 1270 nm phosphorescence (a(1)Delta(g) --> X(3)Sigma(g)(-)) with subcellular spatial resolution. The singlet oxygen lifetime determines its diffusion distance and hence the intracellular volume element in which singlet-oxygen-initiated perturbation of the cell occurs. In this study, the time-resolved phosphorescence of singlet oxygen produced by the sensitizers chlorin (Chl) and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) was monitored. These molecules localize in different domains of a living cell. The data indicate that (i) the singlet oxygen lifetime and (ii) the rate constant for singlet oxygen quenching by added NaN(3) depend on whether Chl or TMPyP was the photosensitizer. These observations likely reflect differences in the chemical and physical constituency of a given subcellular domain (e.g., spatially dependent oxygen and NaN(3) diffusion coefficients), thereby providing evidence that singlet oxygen responds to the inherent heterogeneity of a cell. Thus, despite a relatively long intracellular lifetime, singlet oxygen does not diffuse a great distance from its site of production. This is a consequence of an apparent intracellular viscosity that is comparatively large.

中文翻译：

细胞中的单线态氧：空间相关的寿命和淬火速率常数

单线态分子氧 O(2)(a(1)Delta(g)) 可以在单个细胞中由基态氧 O(2)(X(3)Sigma(g)(-)) 产生，在细胞内敏化剂的聚焦激光照射下。随后可以通过其 1270 nm 磷光 (a(1)Delta(g) --> X(3)Sigma(g)(-)) 与亚细胞空间分辨率检测到这种细胞毒性物种。单线态氧的寿命决定了它的扩散距离，因此决定了细胞内单线态氧引发的扰动发生的细胞内体积元素。在这项研究中，监测了敏化剂二氢卟酚 (Chl) 和 5,10,15,20-四(N-甲基-4-吡啶基)-21H,23H-卟吩 (TMPyP) 产生的单线态氧的时间分辨磷光. 这些分子位于活细胞的不同区域。数据表明 (i) 单线态氧寿命和 (ii) 添加 NaN(3) 的单线态氧猝灭速率常数取决于 Chl 或 TMPyP 是光敏剂。这些观察结果可能反映了给定亚细胞域的化学和物理选区的差异（例如，空间依赖的氧和 NaN(3) 扩散系数），从而提供了单线态氧响应细胞固有异质性的证据。因此，尽管细胞内寿命相对较长，但单线态氧不会从其产生部位扩散很远的距离。这是相对较大的表观细胞内粘度的结果。这些观察结果可能反映了给定亚细胞域的化学和物理选区的差异（例如，空间依赖的氧和 NaN(3) 扩散系数），从而提供了单线态氧响应细胞固有异质性的证据。因此，尽管细胞内寿命相对较长，但单线态氧不会从其产生部位扩散很远的距离。这是相对较大的表观细胞内粘度的结果。这些观察结果可能反映了给定亚细胞域的化学和物理选区的差异（例如，空间依赖的氧和 NaN(3) 扩散系数），从而提供了单线态氧响应细胞固有异质性的证据。因此，尽管细胞内寿命相对较长，但单线态氧不会从其产生部位扩散很远的距离。这是相对较大的表观细胞内粘度的结果。

更新日期：2009-01-14

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