Faculty of Chemistry, University of Warsaw, Poland.
Anal Chem. 2013 Jan 2;85(1):355-61. doi: 10.1021/ac302897f. Epub 2012 Dec 13.
Examination of the attack of OH radicals produced in the Fenton way on DNA molecules is important from biological, biochemical, and biosensor points of view. Calf thymus DNA was selected for the investigation, since this natural oligonucleotide is often used in examination of drug-DNA interactions. Particularly useful was the coherent application of five techniques: electrochemical quartz crystal microbalance (EQCM), square wave voltammetry (SWV), circular dichroism (CD), atomic force microscopy (AFM), and UV-vis spectroscopy. These techniques differ in sensitivity to radical concentration and layer thickness of DNA. EQCM appeared to be the most sensitive in monitoring the consequences of OH radical actions; radical activities corresponding to nanomolar concentrations of H(2)O(2) could be detected. SWV and AFM detection gave noticeable signal for higher than 1 μM H(2)O(2) concentrations. EQCM data led to a conclusion that at higher than 1 μM H(2)O(2) concentrations the DNA strands were locally disintegrated. The corresponding DNA loss was ca. 16%. It has been shown that in the presence of α-tocopherol, a strong antioxidant, the damage caused by OH radicals was practically prevented.
从生物学、生物化学和生物传感器的角度来看，研究芬顿试剂产生的 OH 自由基对 DNA 分子的攻击非常重要。小牛胸腺 DNA 被选为研究对象，因为这种天然寡核苷酸常用于研究药物-DNA 相互作用。电化学石英晶体微天平 (EQCM)、方波伏安法 (SWV)、圆二色性 (CD)、原子力显微镜 (AFM) 和紫外可见光谱法这五种技术的协同应用特别有用。这些技术在检测自由基浓度和 DNA 层厚度方面的灵敏度不同。EQCM 在监测 OH 自由基作用的后果方面似乎最为敏感；可以检测到对应于毫摩尔浓度 H(2)O(2)的自由基活性。SWV 和 AFM 检测在高于 1 μM H(2)O(2)浓度时给出了明显的信号。EQCM 数据得出结论，在高于 1 μM H(2)O(2)浓度时，DNA 链局部解体。相应的 DNA 损失约为 16%。已经表明，在抗氧化剂 α-生育酚存在的情况下，OH 自由基造成的损伤几乎可以被预防。
