| 阴离子黏土(层状双氢氧化物)对鲱鱼精DNA在重金属作用下的保护作用研究 |
| 摘要点击 2501 全文点击 1240 投稿时间：2011-12-15 修订日期：2012-02-21 |
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| 中文关键词 纳米复合体 电化学法 插层 沟区作用 构象 |
| 英文关键词 nanohybrids electrochemistry method intercalation groove binding configuration |
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| 中文摘要 |
| 用X射线衍射(XRD)、傅立叶红外光谱(FTIR)、扫描电镜(SEM)、循环伏安法、紫外光谱法等方法,研究了在重金属Cd2+、Pb2+作用下,阴离子黏土(LDH)对鲱鱼精DNA的保护作用. 实验表明,LDH层间距由0.76 nm增大到2.30 nm,DNA-LDH复合体上出现了DNA分子中骨架和碱基上的C=O (1534 cm-1和1488 cm-1),C—O伸缩振动峰 (1228 cm-1), P—O对称伸缩振动(1096 cm-1),说明 DNA 已通过离子交换插入LDH的层间. 然而DNA分子并没有完全交换出LDH层中NO3-(DNA部分嵌入),未交换到层间的DNA分子通过吸附作用固定于LDH表面上. 循环伏安曲线显示,DNA-LDH复合体中的DNA还原峰与原始DNA保持一致,两个还原峰出现在EP=-1.2 mV和EP=-2.4 mV位置,也没有产生阴极凹陷. 这表明当DNA固定在LDH上时,Cd2+、Pb2+就不能插入DNA沟槽之中,与碱基或其它基团的发生缔合作用. 研究结果表明,一方面, LDH吸附溶液中的Cd2+、Pb2+于外表面上从而固定Cd2+、Pb2+,另一方面,LDH层板为DNA提供了保护空间,阻止Cd2+、Pb2+进入层间域与DNA作用从而保护DNA分子. |
| 英文摘要 |
| The role of layered double hydroxide (LDH) in the protection of herring testis DNA from heavy metals Cd2+and Pb2+ was studied by X-ray diffraction(XRD)spectra,Fourier transform infrared(FTIR)spectra,Scanning Electron Microscopy(SEM),Cyclic Voltammetry and Ultraviolet Spectrometry.Size expansion of the basal spacing (003) from 0.76 nm in LDH to 2.30 nm was observed in the resulting DNA-LDH nanohybrids and it gave peaks corresponding to C=O (1534 cm-1 and 1488 cm-1) in skeleton and bases, C—O stretching vibration (1228 cm-1), and P—O symmetrical stretching vibration (1096 cm-1) in functional groups of DNA, indicating that DNA were intercalated into the LDH by the ion exchange. However, the displacement of NO3- was not fully complete (partial intercalation of DNA). The DNA outside LDH interlayers was absorbed on the surface of LDH. The cyclic voltammetric curves showed that DNA in the composites exhibited a very similar peaks, which corresponded to the two reduction current peaks (EP=-1.2 mV and EP=-2.4 mV) of free DNA. Also there was no cathode sag emerging in cyclic voltammetric curves, suggesting that both Cd2+and Pb2+ cannot insert into the groove of DNA to associate with base pairs or other groups when DNA was bound on LDH. The results showed that, on the one hand, both Cd2+and Pb2+ were absorbed on the external surface of LDH for immobilization, on the other hand, the layer of LDH provided ideal space for DNA by the action of protecting DNA molecules from Cd2+and Pb2+. |
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