基于单壁碳纳米管和目标诱导适体转移电化学适体传感器检测腺苷

Single wall carbon nanotubes modified electrochemical aptasensor for the determination of adenosine based on the target-induced aptamer displacement

以修饰于电极表面的单壁碳纳米管(SWNTs)作为适体固定平台,基于目标诱导适体(Aptamer)转移,构建了检测腺苷的电化学适体传感器。将SWNTs修饰到玻碳电极表面,没有目标物腺苷时,亚甲基蓝标记的腺苷适体(MB-Aptamer)通过适体与SWNTs之间强的相互作用固定在电极表面,此时电极表面因为有大量MB存在,能够检测到强的MB氧化电流信号。当引入腺苷后,因为腺苷与适体的相互作用力大于适体与SWNTs的相互作用力,迫使MB-Aptamer脱离电极进入溶液,此时电极表面MB量减少,导致MB氧化电流强度减弱,根据加入腺苷前后传感器表面MB氧化电流强度的变化,采用方波脉冲伏安法对腺苷进行检测。结果表明,MB氧化电流信号比值与腺苷浓度在0.0010~0.50 nmol/L之间呈良好的线性关系,检出限为0.49 pmol/L(S/N=3)。

A simple and highly sensitive electrochemical aptasensor for the determination of adenosine,based on the target-induced aptamer displacement and the interaction between the aptamer and the single wall carbon nanotubes（SWNTs）,was developed.The methyl blue labeled adenosine aptamer（MB-Aptamer） was fixed on the surface of glass carbon electrode（GCE） modified with the SWNTs by the interaction between the aptamer and the SWNTs.In the absence of the adenosine,the strong current signal was observed because of the large number of MB on the electrode.Introduction of adenosine induced the displacement of the MB-Aptamer from the SWNTs modified on the electrode into the solution,decreasing the current signal of the aptasensor.The interaction between MB-Aptamer and adenosine was monitored by the cyclic voltammetry（CV） and square wave voltammetry（SWV） using MB as probe.The oxidation peak current of MB detected by SWV was linear over the range from 0.0010 to 0.50 nmol/L,with a detection limit of 0.49 pmol/L.