物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1127-1133.doi: 10.3866/PKU.WHXB201203073

电化学和新能源 上一篇    下一篇

电化学和紫外-可见吸收光谱法研究pH和金纳米粒子对细胞色素c的影响

王艳艳1, 姜艳霞1, 沙德礼2, 罗德礼2, 孙世刚1   

  1. 1. 厦门大学化学化工学院化学系, 固体表面物理化学国家重点实验室, 福建厦门 361005;
    2. 香港城市大学物理与材料科学系, 香港
  • 收稿日期:2012-01-13 修回日期:2012-02-29 发布日期:2012-04-26
  • 通讯作者: 姜艳霞 E-mail:yxjiang@xmu.edu.cn
  • 基金资助:

    国家自然科学基金(20833005, 20873116, 60936003, 21021002)资助项目

Effect of pH and Au Nanoparticles on Cytochrome c Investigated by Electrochemistry and UV-Vis Absorption Spectroscopy

WANG Yan-Yan1, JIANG Yan-Xia1, SUSHAAndrei2, ROGACH Andrey2, SUN Shi-Gang1   

  1. 1. Key Laboratory of Physical Chemistry of Solid Surface, Department of Chemistry, College of Chemistry and Chemistry Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China;
    2. Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, P. R. China
  • Received:2012-01-13 Revised:2012-02-29 Published:2012-04-26
  • Contact: JIANG Yan-Xia E-mail:yxjiang@xmu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20833005, 20873116, 60936003, 21021002).

摘要: 制备了粒径均匀、平均粒子尺度为(4.7±0.6) nm, 表面修饰3-巯基丙酸(MPA)的金纳米粒子(Au NPs).利用电化学和紫外-可见(UV-Vis)吸收光谱研究了pH和Au NPs对细胞色素c (Cyt c)结构的影响. UV-Vis 吸收光谱结果表明, pH为7.5-3.0 时, Cyt c 和Cyt c-Au NPs复合物的结构没有发生明显变化. 当pH=2.0 时, Cyt c和Cyt c-Au NPs复合物的Soret 谱峰位置均发生明显移动, 说明pH诱导其构象发生变化. 循环伏安(CV)结果表明, 表面修饰了MPA的Au NPs能促进Cyt c 和电极之间的电子传输, 与修饰了柠檬酸根的Au NPs相比, 其生物兼容性更好. pH的变化会引起CV中Cyt c 峰电流的改变和峰电位的移动. 随着pH值的降低, Cyt c 电活性的量逐渐减小, 并且pH诱导Cyt c 发生不可逆变性. Au NPs的引入使自由态的Cyt c 耐酸性增强, 而使得吸附态的Cyt c 耐酸能力减弱.

关键词: 金纳米粒子, 细胞色素c, pH值, 循环伏安法, 紫外-可见吸收光谱

Abstract: In this paper, gold nanoparticles (NPs) with an average size of (4.7 ± 0.6) nm, capped with mercaptopropionic acid (MPA) ligand, are prepared. The effect of pH and Au NPs on cytochrome c (Cyt c) is investigated by electrochemistry and UV-Vis absorption spectroscopy. UV-Vis absorption spectra indicate that the structures of Cyt c and Cyt c-Au NPs complex do not change appreciably between pH=7.5 and pH=3.0, but their Soret band positions change markedly at pH=2.0, indicating that low pH value induces a conformational change in Cyt c. Cyclic voltammetry (CV) result shows that Au NPs capped with MPA enhance electron transfer between Cyt c and the electrode. The data also reveals that the biocompatibility of Au NPs is improved when citric acid ligand is replaced with MPA. The change in pH value causes a change of peak currents in CV and a shift of peak potential. When pH value deviates from 7.0, levels of electroactive Cyt c decrease. Significant pH change induces irreversible denaturing of Cyt c. The pH at which Cyt c-Au NPs complex denatures completely is one unit higher than that of Cyt c. Combining the results from UV-Vis spectroscopy and CV, we find that addition of Au NPs makes adsorbing state Cyt c more vulnerable to pH.

Key words: Au nanoparticle, Cytochrome c, pH value, Cyclic voltammetry, UV-Vis absorption spectroscopy

MSC2000: 

  • O646