基于信号增强的电化学发光适配体传感器检测三磷酸腺苷

Electrochemiluminescent Aptasensor Based on Signal Enhancement for Determination of Adenosine Triphosphate

基于三磷酸腺苷(ATP)适配体与ATP分子作用后可以显著增强电化学发光信号的性能,研究了一种用于ATP含量检测的电化学发光适配体(ECL-aptamer)传感器。通过电沉积方法获得纳米金电极。3′端标记联吡啶钌发光分子的探针DNA通过5′端修饰的巯基自组装到纳米金电极表面,然后与5′端标记二茂铁分子的ATP核酸适配体互补杂交,形成刚性线形的双链DNA,由此构建的传感器产生较弱的电化学发光(ECL)信号。该传感器在ATP溶液中孵化后,由于ATP分子与ATP适配体强的特异性结合,使得适配体分子与探针DNA分子解离,从电极表面脱落进入溶液,此时电极表面的探针DNA在强电解质溶液中可以形成发卡型的茎环结构,产生显著增强的ECL信号。ECL信号强度与ATP浓度的对数值呈线性关系,线性范围为10.0~1.0×105 pmol/L,相关系数r=0.9959,检测限为5.0 pmol/L。该传感器的灵敏度与检测范围高于目前已报道的结果,显示出了ATP检测的应用潜力。

Based on the property that the electrochemiluminescence(ECL)signal could be significantly enhanced after adenosine triphosphate(ATP)aptamers interacted with ATP molecules,an ECL aptasensor was developed to detect ATP.A nano-Au electrode was obtained by electrodeposition method.The probe DNA with 3′-terminal labeled by ruthenium complex was self-assembled to the surface of the nano-Au electrode with the sulfhydryl group modified on the 5′-terminal,and then hybridized with the ATP aptamer which 5′-terminal was labeled by ferrocene molecule,to form rigid linear double-stranded DNA.Thus,the constructed sensor produced weak ECL signal.After incubation in an ATP solution,the aptamer molecules could dissociate from the probe DNA and fall off from the electrode surface due to the strong specific binding of ATP molecules and ATP aptamer,and the probe DNA on the electrode surface could form hairpin like stem ring structure,resulting in a stronger ECL signal.The linear range of ECL intensity and the logarithm of the ATP concentration was 10.0~1.0×105 pmol/L with a detection limit of 5.0 pmol/L,and the correlation coefficient was 0.9959.The sensitivity and detection range of the sensor are higher than those reported so far,which shows the potential application of ATP detection.