物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1163-1168.doi: 10.3866/PKU.WHXB201202241

电化学和新能源 上一篇    下一篇

基于ITO电极的细胞色素c吸附层的直接电化学

张喆, 祁志美, 张蓉君   

  1. 中国科学院电子学研究所, 传感技术国家重点实验室, 北京 100190
  • 收稿日期:2011-12-02 修回日期:2012-02-16 发布日期:2012-04-26
  • 通讯作者: 祁志美 E-mail:zhimei-qi@mail.ie.ac.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2009CB320300), 国家自然科学基金(60978042, 61078039)和中国科学院“百人计划”择优支持项目资助

Direct Electrochemistry of Cytochrome c Adlayer on the ITO Electrode

ZHANG Zhe, QI Zhi-Mei, ZHANG Rong-Jun   

  1. State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2011-12-02 Revised:2012-02-16 Published:2012-04-26
  • Contact: QI Zhi-Mei E-mail:zhimei-qi@mail.ie.ac.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2009CB320300), National Natural Science Foundation of China (60978042, 61078039), and BaiRenJiHua Program of Chinese Academy of Sciences.

摘要: 采用未经修饰的铟锡氧化物(ITO)工作电极直接探测到了细胞色素c (Cyt c)吸附层的氧化还原峰, 并得出了Cyt c 的表面浓度, 随着溶液浓度从2 μmol·L-1增大到10 μmol·L-1, Cyt c 的表面浓度相应地从0.35×10-12mol·cm-2增大到1.53×10-12 mol·cm-2. 实验获得的表面浓度倒数与溶液浓度倒数的准线性关系说明Cyt c 在ITO表面的吸附基本满足Langmuir 等温吸附理论. 对Cyt c 溶液的循环伏安测试结果表明参与电极反应的Cytc 包括游离分子和吸附分子, 前者的贡献大于后者, 电极反应主要受扩散控制并呈准可逆过程. 根据Nicholson方法估算得到反应物的标准异相速率常数的平均值为1.65×10-3 cm·s-1. 实验结果显示在室温下放置1 h 后Cyt c 吸附层电化学活性部分丧失, 在80 °C下放置1 h 后吸附层完全失活. 失活的Cyt c 吸附层对铁氰化钾溶液在Au电极上的电极反应具有明显的阻碍作用.

关键词: 细胞色素c吸附层, 直接电化学, Langmuir等温吸附, 表面浓度

Abstract: The electrochemical redox reaction of a cytochrome c (Cyt c) adlayer on an indium tin oxide (ITO) electrode was directly monitored and the surface concentrations of Cyt c versus solution concentrations were obtained from cyclic voltammograms. The results indicate that the surface concentration increases from 0.35 × 10-12 to 1.53 × 10-12 mol·cm-2 when the solution concentration is increased from 2 to 10 μmol ·L-1. A quasi-linear relationship between the reciprocals of surface concentration and solution concentration was observed, indicating that Cyt c adsorption on the ITO electrode closely obeys the Langmuir isothermal adsorption model. The cyclic voltammograms of the Cyt c solutions with the ITO electrode reveal that both adsorbed and dissociated Cyt c molecules are involved in the electrode reaction and that the contribution of dissociated molecules is much larger than that of adsorbed ones. The electrode reaction is basically diffusion controlled and quasi-reversible. Based on the Nicholson method, the average standard heterogeneous rate constant was determined to be 1.65×10-3 cm· s-1. The electrochemical activity of the Cyt c adlayer was partially lost when it was kept at 25 °C for 1 h, and was completely lost at 80 °C. The denatured Cyt c adlayer on a gold electrode can effectively inhibit the electrode reaction of K3Fe(CN)6 solution.

Key words: Cytochrome c adlayer, Direct electrochemistry, Langmuir isothermal adsorption, Surface concentration

MSC2000: 

  • O646