物理化学学报 >> 2012, Vol. 28 >> Issue (10): 2258-2262.doi: 10.3866/PKU.WHXB201208281

电化学和新能源 上一篇    下一篇

离子强度对DNA媒介电荷转移的影响——基于Debye-Hückel 理论的实验结果分析

冀中华1, 朱斌1, 李经建1, 蔡生民1, 袁谷2, 徐东升1   

  1. 1 北京大学化学与分子工程学院物理化学研究所, 北京分子科学国家实验室, 北京 100871;
    2 北京大学化学与分子工程学院化学生物学系, 教育部生物有机与分子工程重点实验室, 北京 100871
  • 收稿日期:2012-08-01 修回日期:2012-08-27 发布日期:2012-09-26
  • 通讯作者: 李经建 E-mail:lijj@pku.edu.cn
  • 基金资助:

    国家自然科学基金(20573008)资助项目

Influence of Ionic Strength on DNA Mediated Charge Transport——Experiments and the Related Debye-Hückel Theory

JI Zhong-Hua1, ZHU Bin1, LI Jing-Jian1, CAI Sheng-Min1, YUAN Gu2, XU Dong-Sheng1   

  1. 1 Beijing National Laboratory for Molecular Sciences, Institute of Physical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China;
    2 Department of Chemical Biology, The Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2012-08-01 Revised:2012-08-27 Published:2012-09-26
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20573008).

摘要:

用电化学的方法研究了溶液离子强度对DNA媒介电荷转移的影响, 观察到[Ru(NH3)6]3+的还原峰电势随支持电解质的浓度增加向负方向移动. 分析发现微分脉冲伏安法(DPV)的峰电势与溶液离子强度间在一定范围内存在线性关系, 以式电势(E0')作为“桥梁”, 用Debye-Hückel理论给予了解释. 在高离子强度下, 峰电势对线性关系的偏移是由于超过了Debye-Hückel理论的适用范围, 而无强电解质存在时, DNA自身堆积的强负电荷对DNA媒介电荷转移起了推动作用.

关键词: 离子强度, Debye-Hü, ckel理论, DNA小沟, 拓展π堆积, 电荷转移

Abstract:

The ionic strength dependence of DNA mediated charge transport was studied on a DNA binding polyamide-modified electrode by the electrochemical method. The differential pulse voltammetry (DPV) peak potential of [Ru(NH3)6]3+ shifted negatively with the increase of support electrolyte concentration. Linear relationship between peak potential and ionic strength in the solution was found at the range of moderate salt concentration, which can be interpreted with Debye-Hückel theory using formal potential as a “bridge” linked experiments results and theoretical calculated values. Under high salt concentration this linear relationship deviated from Debye-Hückel theory prediction due to its range of validity is overstep. Without added salt in the solution, fully charged DNA duplex will strongly attract the probe molecule [Ru(NH3)6]3+ to the broadened p-stack of a DNA-polyamide complex, which facilitated DNA mediated charge transport.

Key words: Ionic strength, Debye-Hü, ckel theory, DNA minor groove, Broadened π-stack

MSC2000: 

  • O641