Sensitive Electrochemical Aptasensor by Coupling "Signal-on" and "Signal-off" Strategies
Sensitive Electrochemical Aptasensor by Coupling "Signal-on" and "Signal-off" Strategies
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通过耦合“信号开启”和“信号关闭”策略的灵敏电化学适体传感器
DOI：
10.1021/ac401810t
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发表时间：
2013
影响因子：
7.4
通讯作者：
Chen Jinhua
中科院分区：
文献类型：
--
作者：
Wu Liang;Zhang Xiaohua;Liu Wei;Xiong Erhu;Chen Jinhua
基于一种新的双信号放大策略，研制了一种简便、灵敏、选择性测定三磷酸腺苷（ATP）的电化学配体传感器。这种感应传感器具有“信号开启”和“信号关闭”两种元素。二茂铁（Fc）标记的适体探针（Fc- p）与硫代亚甲基蓝（MB）修饰的DNA探针（MB- p）在金电极上杂交形成刚性双链DNA。在ATP存在的情况下，ATP与适体之间的相互作用导致双链DNA结构的解离，从而使Fc-P从传感界面释放出来。单链MB-P可以通过其两端互补序列的杂交形成发夹结构。这种构象变化导致Fc的氧化峰电流减小，MB的氧化峰电流增大，双信号的变化与ATP浓度呈线性关系。以“ΔI= ΔIMB+ |ΔIFc|”（ΔIMBand ΔIFcare分别为MB和Fc的氧化峰电流变化值）作为响应信号定量测定ATP时，检测限（1.9 nM）远低于单独使用MB- p或Fc- p。这种新的双信号感应体易于再生，并且对目标具有良好的响应。在其他小分子和蛋白质的灵敏和选择性电化学测定中具有重要的应用价值。
A simple electrochemical aptasensor for sensitive and selective determination of adenosine triphosphate (ATP) has been developed on the basis of a new dual-signaling amplification strategy. This aptasensor features both ‘‘signal-on’’ and ‘‘signal-off’’ elements. The ferrocene (Fc)-labeled aptamer probe (Fc-P) is designed to hybridize with the thiolated methylene blue (MB)-modified DNA probe (MB-P) on gold electrode to form rigid duplex DNA. In the presence of ATP, the interaction between ATP and the aptamer leads to the dissociation of the duplex DNA structure and thereby the release of the Fc-P from the sensing interface. The single-stranded MB-P could thus tend to form a hairpin structure through the hybridization of the complementary sequences at both its ends. Such conformational changes result in the oxidation peak current of Fc decreases and that of MB increases, and the changes of dual signals are linear with the concentration of ATP. When “ΔI= ΔIMB+ |ΔIFc|” (ΔIMBand ΔIFcare the change values of the oxidation peak currents of MB and Fc, respectively.) is used as the response signal for quantitative determination of ATP, the detection limit (1.9 nM) is much lower than that by using either MB-P or Fc-P alone. This new dual-signaling aptasensor is readily regenerated and shows good response toward the target. It will have important applications in the sensitive and selective electrochemical determination of other small molecules and proteins.