Oxidative damage to nucleic acids photosensitized by titanium dioxide
Oxidative damage to nucleic acids photosensitized by titanium dioxide
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DOI：
10.1016/s0891-5849(97)00068-3
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发表时间：
1997-01-01
影响因子：
7.4
通讯作者：
Wei, RR
中科院分区：
文献类型：
--
作者：
Wamer, WG;Yin, JJ;Wei, RR
已知半导体TiO2在原核和真核细胞中具有光生物活性。这种光生物活性的应用包括废水的灭菌和恶性细胞的光疗。本文采用了几种模型和细胞系统来研究TiO2光催化的机理。二氧化钛（锐钛矿，0.45 μ m）悬浮在含有自旋捕集器5,5-二甲基-1-吡咯烷- n -氧化物（DMPO）的水中，用紫外辐射（320 nm）处理后，羟基自由基具有电子自旋共振（ESR）信号特征。用UVA （320-400 nm）照射含有小牛胸腺DNA和TiO2的溶液可导致鸟嘌呤碱基羟基化。羟基化的程度取决于UVA的影响和悬浮中TiO2的量。用10 μ g/cm(2) TiO2预孵育18 h，然后用uva照射（0-58 KJ/m(2)），人皮肤成纤维细胞表现出剂量依赖性的光细胞毒性。从类似处理的成纤维细胞中分离出的RNA含有显著水平的光氧化，通过鸟嘌呤碱基的羟基化来测量。然而，在细胞DNA中没有检测到氧化损伤。这些结果表明，核酸是TiO2致敏光氧化损伤的潜在靶点，并支持TiO2光催化自由基形成的观点。Elsevier Science Inc.出版。
The semiconductor TiO2 is known to have photobiological activity in prokaryotic and eukaryotic cells. Applications of this photobiological activity have been suggested including sterilization of waste water and phototherapy of malignant cells. Here, several model and cellular systems were used to study the mechanism of photocatalysis by TiO2. Treatment of TiO2 (anatase, 0.45 mu m), suspended in water containing a spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), with UV radiation (320 nm) resulted in an electron spin resonance (ESR) signal characteristic of the hydroxyl radical. Irradiation of solutions containing calf thymus DNA and TiO2 with UVA (320-400 nm) radiation resulted in hydroxylation of guanine bases. The degree of hydroxylation was dependent on both UVA fluence and amount of TiO2 in suspension. Human skin fibroblasts, preincubated 18 h with 10 mu g/cm(2) TiO2 and then UVA-irradiated (0-58 KJ/m(2)), showed dose dependent photocytoxicity. RNA, isolated from similarly treated fibroblasts, contained significant levels of photooxidation, measured as hydroxylation of guanine bases. However, no oxidative damage was detectable in cellular DNA. These results suggest that nucleic acids are a potential target for photooxidative damage sensitized by TiO2, and support the view that TiO2 photocatalyzes free radical formation. Published by Elsevier Science Inc.