【作者】 李萌；

【导师】 鲁理平；

【作者基本信息】 北京工业大学 ， 环境科学与工程， 2013， 硕士

【摘要】 全氟有机化合物（PFCs）自1951年由3M公司研制成功以后，由于其具有较好的热稳定、化学稳定、高表面活性以及疏水疏油性能被广泛地应用于工业生产和生活领域。在全氟烷基化合物中，碳链长度为8的长链羧酸或磺酸类化合物占了较大的比例，而且这些长链羧酸和磺酸类化合物的最终降解产物多为全氟辛酸PFOA （Perfluorooctanoic Acid）和全氟辛烷磺酸PFOS （perfluorooctanesulfonate）。2009年5月，在关于持久性有机污染物的第四次缔约大会上，将PFCs中的全氟辛磺酸及其盐和全氟辛基磺酰氟列入了《斯德哥尔摩公约》。研究表明PFOA能通过呼吸道吸入和饮用水、食物的摄入等方式进入生物体，且很难被排出，最终富集于人体、生物体中的血、肝脏、肾脏和脑中，引发毒性作用，在美国国家环保局（EPA）科学顾问委员会报告中，已经将PFOA称之为“可能的（likely）致癌物”或者“提示性（suggestive）致癌物”。目前PFOA的毒性机理还不清楚，也鲜有基于分子水平的研究成果。电化学DNA传感器是研究DNA损伤的有利工具，电化学发光方法具有更高的灵敏性。本论文将采用电化学和电化学发光的方法研究PFOA和DNA的相互作用形式。具体研究内容包括：1.将CdSe纳米晶和DNA分子通过自组装的方法固载在金电极表面构建了CdSe-dsDNA/Au电化学发光传感器，共反应剂K2S2O8的条件下考察电化学发光强度在PFOA温浴前后的变化研究了PFOA对DNA的损伤作用。传感器的界面通过原子力显微镜和电化学阻抗进行了表征，得到了满意的结果。同时以亚甲基蓝（MB）为电化学指示剂检测其峰电流和峰电位的变化及X射线光电子能谱（XPS）的分析佐证了PFOA对DNA的损失作用。2.在以上实验的基础上，将CdSe-dsDNA组装在纳米金表面，发现CdSe量子点的电化学发光发生了淬灭现象。根据相关文献探讨了金纳米颗粒在一定的条件下对电化学发光产生淬灭的作用。接着我们以小牛胸腺ct-DNA替代了短链的DNA分子构建了CdSe-ctDNA-AuNPs（纳米金）电化学发光传感器，并研究了PFOA对小牛胸腺ct-DNA的损伤作用。经过实验研究发现，修饰在电极上的金纳米颗粒与量子点间的距离较近时会发生淬灭作用，而有趣的是CdSe-ct-DNA/AuNPs/GCE的电化学发光强度比CdSe-dsDNA/AuNPs/GCE发光强度有明显增大，该结果验证了纳米金在特定条件下的淬灭现象。3.鉴于DNA与钌配合物的作用机理已被晶体学所证实，为进一步考察DNA与PFOA的作用机理，利用[Ru（bpy）₂dppz]²⁺为电化学发光探针研究了PFOA对DNA的损伤作用。实验过程中，制备了电极Ru-dppz/dsDNA/Au，通过对[Ru（bpy）₂dppz]²⁺的电化学发光强度的变化探讨了PFOA对双链dsDNA的损伤；并通过组装单碱基误配MMdsDNA讨论了单碱基误配MMdsDNA与[Ru（bpy）₂dppz]²⁺作用后的电化学发光强度变化，实验发现单碱基误配MMdsDNA的电化学发光强度低于互补双链dsDNA的电化学发光强度，基于此讨论了PFOA对DNA的损伤作用。实验中制备的电极过程具有简单、方便、性质稳定等的性质。通过以上分析讨论，得出环境污染物PFOA可对DNA在分子水平上造成损伤。更多还原

【Abstract】 Perfluorinated organic compounds （PFCs） were successfully developed by the3M Company since1951, because of its good thermal stability, chemical stability,high surface activity and hydrophobic oleophobic can be widely used in industrialproduction and living areas.In the perfluoroalkyl group compound, the carbon chainlength of8compounds accounted for a large proportion of long-chain carboxylic ac-ids or sulfonic acids, and compounds of these long-chain carboxylic acids and sul-fonic acids were final degradated to perfluoro octanoic acid PFOA and perfluorooc-tane sulfonic acid PFOS. In05/2009, the Fourth Conference of the Contracting onPersistent Organic Pollutants, PFCs, perfluorooctanoic acid and its salts and perfluo-rooctane sulfonyl fluoride were included in the Stockholm Convention.Several re-searches have shown that PFOS are well absorbed after oral uptake and are primarilyfound by biological methods in the liver, plasma, and kidney, which can lead to toxiceffects. In the proceedings of the national environental protection bureau （EPA） scien-tific advisory committee report, PFOA have calls "（likely） carcinogens may" or"（suggestive） carcinogens of presentation.Now the toxic mechanism of PFOS is un-clear and there are few research results of the interaction mechanism between PFOSand DNA based on the molecular level.The electrochemical DNA sensor is a powerfultool to study DNA damage.This thesis studied the interaction mechanism betweenPFOS and DNA using the electrochemical and electrochemiluminescence method.Indetails, the content including as follows:1. The nanocrystalline CdSe and DNA molecules is immobilized on the goldelectrode surface by self-assembly method to construct the CdSe-dsDNA/Au electro-chemical luminescence sensors, and K2S2O8was used as coreactant to study the DNAdamage induced by PFOA.Sensor interface has been characterized by atomic forcemicroscopy and electrochemical impedance, and satisfactory results were obtained.And methylene blue （MB） was used as the electrochemical indicator to detect changesof the peak current and peak potential, and then X-ray photoelectron spectroscopy（XPS） analysis was proved DNA damage.2. On the basis of the above experiment, the CdSe-dsDNA assembled on thesurface of gold nanoparticles, found that electrochemical CdSe quantum dot lumines-cence quenching phenomenon occurs. According to the related literature on the goldnanoparticles under certain conditions on the electrochemical luminescence quench-ing effect produced. Then we with calf thymus ct-DNA replaced the DNA moleculesof short chain constructed CdSe-ct-DNA-AuNPs （Gold nanoparticles） electrochemicalluminescence sensors, and studied the PFOA of calf thymus ct-DNA damage ef-fect.Through the experimental study found, modified gold nanoparticles and quantum dots on the electrode distance closer occurs when quenching, but interestinglyCdSe-ct-DNA/AuNPs/GCE electrochemical luminescence intensity ratio ofCdSe-dsDNA/AuNPs/GCE emission intensity has increased significantly, the resultsverify the gold nanoparticles in the specific conditions of the quenching phenomenon.3. In view of the mechanism of DNA and ruthenium complexes have been con-firmed by crystallography, to further review the mechanism of DNA with PFOA, anduse [Ru（bpy）₂dppz]²⁺as the electrochemical luminescence probe for the study of thePFOA effect on DNA damage. During the experiments, Ru-dppz/dsDNA/Au elec-trode was prepared, based on the electrochemical luminescence intensity of[Ru（bpy）₂dppz]²⁺to study the PFOA on dsDNA damage; And through the assemblewith MMdsDNA discussed the electrochemical luminescence intensity changes ofMMdsDNA and [Ru（bpy）₂dppz]²⁺,it was found that the electrochemical lumines-cence of MMdsDNA is lower than the dsDNA, based on this phenomenon discussesthe PFOA effect on DNA damage. The preparation of electrode process has the prop-erties of simple preparation, convenient, stable property.Through the above analysis, the environmental pollutants PFOA can cause dam-age of DNA at the molecular level.更多还原