Far-Red Fluorescence Probe for Monitoring Singlet Oxygen during Photodynamic Therapy
Far-Red Fluorescence Probe for Monitoring Singlet Oxygen during Photodynamic Therapy
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DOI：
10.1021/ja504279r
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发表时间：
2014-08-20
影响因子：
15
通讯作者：
Majima, Tetsuro
中科院分区：
文献类型：
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作者：
Kim, Sooyeon;Tachikawa, Takashi;Majima, Tetsuro
单线态氧（O-1（2））是处于最低激发态的分子氧，在光动力疗法（PDT）的细胞杀伤机制中具有关键作用。虽然O-1（2）磷光测量主要用于监测PDT过程中O-1（2）的形成，但其强度远不足以使用现有的近红外探测器获得具有亚细胞空间分辨率的细胞内O-1（2）的二维图像。本文提出了一种新的O-1（2）的远红外荧光探针Si-DMA，它由含硅的罗丹明和蒽基团组成，分别作为发色团和O-1（2）反应位点。在O-1（2）存在下，由于蒽部分形成内过氧化物，Si-DMA的荧光增强17倍。由于光照射的自氧化作用可以忽略不计（Phi（Delta）< 0.02）和选择性线粒体定位的优点，Si-DMA特别适合在PDT期间成像O-1（2）。在三种不同的细胞内光敏剂（Sens）中，Si-DMA可以选择性地检测由5-氨基乙酰丙酸衍生的原卟啉IX产生的O-1（2），其与Si-DMA共定位于线粒体中。另一方面，线粒体靶向的KillerRed和溶酶体卟啉不能诱导Si-DMA的荧光变化。取决于Sens定位和光敏化机制的Si-DMA响应的这种令人惊讶的选择性分别是由有限的细胞内O-1（2）扩散距离（类似于300 rim）和I型Sens产生的O-1（2）可忽略不计引起的。这是我们第一次成功地以单个线粒体小管的空间分辨率可视化PDT过程中产生的O-1（2）。
Singlet oxygen (O-1(2)), molecular oxygen in the lowest excited state, has a critical role in the cell-killing mechanism of photodynamic therapy (PDT). Although O-1(2) phosphorescence measurement has been mainly used to monitor O-1(2) formation during PDT, its intensity is far insufficient to obtain two-dimensional images of intracellular O-1(2) with the subcellular spatial resolution using the currently available near-IR detector. Here, we propose a new far-red fluorescence probe of O-1(2), namely, Si-DMA, composed of silicon-containing rhodamine and anthracene moieties as a chromophore and a O-1(2) reactive site, respectively. In the presence of O-1(2), fluorescence of Si-DMA increases 17 times due to endoperoxide formation at the anthracene moiety. With the advantage of negligible self-oxidation by photoirradiation (Phi(Delta) < 0.02) and selective mitochondrial localization, Si-DMA is particularly suitable for imaging O-1(2) during PDT. Among three different intracellular photosensitizers (Sens), Si-DMA could selectively detect the O-1(2) that is generated by 5-aminolevulinic acid-derived protoporphyrin IX, colocalized with Si-DMA in mitochondria. On the other hand, mitochondriatargeted KillerRed and lysosomal porphyrins could not induce fluorescence change of Si-DMA. This surprising selectivity of Si-DMA response depending on the Sens localization and photosensitization mechanism is caused by a limited intracellular O-1(2) diffusion distance (similar to 300 rim) and negligible generation of O-1(2) by type-I Sens, respectively. For the first time, we successfully visualized O-1(2) generated during PDT with a spatial resolution of a single mitochondrial tubule.