金电极上巯基修饰单链DNA对[Fe(CN)_6]^(3-/4-)的电催化作用  

Electrocatalysis of Thiolated Single Strand DNA on Gold Electrode for [Fe(CN)_6]^(3-/4-)

作　　者：郝青丽[1] 王安子[1] 程荣恩[1] 杨绪杰[1] 陆路德[1] 汪信[1] 

机构地区：[1]南京理工大学化工学院,江苏南京210094

出　　处：《南京理工大学学报》2009年第3期388-392,398,共6页Journal of Nanjing University of Science and Technology

基　　金：江苏省自然科学基金(BK2006201);中国博士后科研基金(20060400285);江苏省博士后科研基金(2006);教育部留学回国人员科研启动基金;人事部留学回国人员科技活动择优资助(科研启动)经费;南京理工大学"百名优秀教师培养计划"资助基金

摘　　要：为研制简易非标记脱氧核糖核酸(DNA)电化学传感器,制备了固定在金电极上的DNA探针。研究了铁氰化钾在裸金电极、巯基化单、双链DNA(HS-ssDNA,HS-dsDNA)修饰金电极上的电化学行为,探讨了铁氰化钾浓度和离子强度对[Fe(CN)6]3-/4-的电化学行为的影响。结果发现:在低离子强度下,HS-ssDNA对[Fe(CN)6]3-/4-的电化学行为有电催化作用,导致[Fe(CN)6]3-/4-在HS-ssDNA修饰的金电极(HS-ssDNA/Au)上的峰电流远远大于在裸电极上的峰电流;而HS-dsDNA则没有这种电催化活性;电极上的DNA杂交后阻碍了电子的传递,导致HS-dsDNA修饰金电极(HS-dsDNA/Au)上的[Fe(CN)6]3-/4-的电化学行为消失;巯基修饰的单链DNA对[Fe(CN)6]3-/4-的电催化具有特异性。The DNA probes immobilized on gold electrodes are prepared for the development of electrochemical label-free DNA sensors. The electrochemical behavior of potassium ferrieyanide is studied using bare gold electrode and the electrodes modified by thiolated single or double strand DNA （HS-ssDNA, HS-dsDNA）. The influence of the ionic strength and the concentration of potassium ferricyanide on the electrochemical behavior is investigated. The electrocatalysis of HS-ssDNA im-mobilized on the electrode is conducted for the redox of [ Fe （CN）6 ]^3-/4- under the condition of low ionic strength, which leads to the higher peak current on the gold electrode modified with HS-ssDNA （HS-ssDNA/Au） than on the bare electrode. Such an electrocatalysis is not observed on the HS-ds- DNA/Au. The electron transfer is blocked due to the hybridization of DNA modified on the electrode. This results in the disappearance of electrochemical activity of [ Fe（CN）6 ]^3-/4- on the gold electrode modified with HS-dsDNA （HS-dsDNA/Au）. The electrocatalysis of HS-ssDNA for [ Fe（CN） 6 ]^3 -/4- is approved specific.

关 键 词：脱氧核糖核酸 金电极 巯基化单链脱氧核糖核酸 [Fe(CN)6]3-/4- 电催化 电化学 

分 类 号：O657.1[理学—分析化学]