Photosensitized breakage and damage of DNA by CdSe-ZnS quantum dots
Photosensitized breakage and damage of DNA by CdSe-ZnS quantum dots
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DOI：
10.1021/jp8018606
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发表时间：
2008-08-14
影响因子：
3.3
通讯作者：
Biju, Vasudevanpillai
中科院分区：
文献类型：
--
作者：
Anas, AbdulAziz;Akita, Hidetaka;Biju, Vasudevanpillai
在不同的光活化条件下研究了 CdSe-ZnS 量子点 (QD) 对质粒 DNA (pDNA) 的链断裂和核碱基损伤。在这里，链霉亲和素功能化的 CdSe-ZnS QD 与生物素化的 pDNA 缀合，并使用原子力显微镜 (AFM) 成像、凝胶电泳分析和活性氧中间体 (ROI) 测定来研究缀合物中的光敏链断裂和核碱基损伤。此外，光活化的 pDNA-QD 缀合物与碱基切除修复酶（例如甲酰胺嘧啶糖基酶 (Fpg) 和核酸内切酶 III (Endo 111)）的反应显示了嘌呤和嘧啶碱基的损伤。碱基切除修复酶识别并去除受损的碱基。光活化 pDNA-QD 缀合物的碱基切除反应导致 pDNA 链断裂，在琼脂糖凝胶图像中显示为剪切带。根据AFM成像、Fpg和Endo III与受损pDNA的反应、ROI测定以及文献报道，我们将pDNA的断裂和损伤归因于其与ROI的反应。通过硝基蓝四唑 (NBT) 测定证实了光活化 QD 产生的 ROI。目前的工作表明，量子点偶联核酸长时间的光活化不利于其稳定性。另一方面，量子点光诱导产生 ROI 是一个新兴的研究领域，在癌症光动力治疗中具有潜在的应用前景。在这方面，当前工作中观察到的 pDNA 光敏损伤表明了量子点在核靶向光动力治疗中的可能性。
Strand breakages and nucleobase damages in plasmid DNA (pDNA) by CdSe-ZnS quantum dots (QDs) are investigated under different conditions of photoactivation. Here, streptavidin functionalized CdSe-ZnS QDs are conjugated to biotinylated pDNA, and photosensitized strand breakages and nucleobase damages in the conjugates are investigated using atomic force microscopy (AFM) imaging, gel electrophoreses analyses, and assay of reactive oxygen intermediates (ROI). Also, reactions of photoactivated pDNA-QD conjugates with base excision repair enzymes such as formamidopyrimidine glycosylase (Fpg) and endonuclease III (Endo 111) show damages of purine and pyrimidine bases. The base excision repair enzymes recognize and remove the damaged bases. The base excision reactions of photoactivated pDNA-QD conjugates resulted in pDNA strand breakages, which appeared as sheared bands in agarose gel images. On the basis of AFM imaging, reactions of Fpg and Endo III with damaged pDNA, ROI assay, and literature reports, we attribute the breakage and damage of pDNA to its reactions with ROI. The production of ROI by photoactivated QDs is confirmed by nitroblue tetrazolium (NBT) assay. The current work shows that photoactivation of QD-conjugated nucleic acids for an extended period of time is not favorable for their stability. On the other hand, photoinduced production of ROI by QDs is an emerging research area with potential applications in the photodynamic therapy of cancer. In this regard, photosensitized damage of pDNA observed in the current work shows possibilities of QDs in nucleus-targeted photodynamic therapy.