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  

Role of Layered Double Hydroxide (LDH) in the Protection of Herring Testis DNA from Heavy Metals

作　　者：唐旖旎[1] 吴平霄[1,2,3] 朱能武[1,2] 

机构地区：[1]华南理工大学环境科学与工程学院,广州510006 [2]工业聚集区污染控制与生态修复教育部重点实验室,广州510006 [3]污染控制与生态修复广东省教育厅重点实验室,广州510006

出　　处：《环境科学》2012年第10期3598-3605,共8页Environmental Science

基　　金：国家自然科学基金项目(41073058;40973075);广东省科技计划项目(2006B36601004;2008B30302036);高等学校博士学科点专项科研基金项目(20100172110028);广东省自然科学基金团队项目(9351064101000001)

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(1 534 cm-1和1 488 cm-1),C—O伸缩振动峰(1 228 cm-1),P—O对称伸缩振动(1 096 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.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 CO（1 534 cm-1 and 1 488 cm-1） in skeleton and bases,C—O stretching vibration（1 228 cm-1）,and P—O symmetrical stretching vibration（1 096 cm-1） in functional groups of DNA,indicating that DNA were intercalated into the LDH by the ion exchange.However,the displacement of NO-3 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＋.

关 键 词：纳米复合体 电化学法 插层 沟区作用 构象 

分 类 号：X131[环境科学与工程—环境科学]