基于计时库仑技术的可再生型三磷酸腺苷适配体电化学传感器的研究

构建了一种可再生型三磷酸腺苷(ATP)适配体计时库仑电化学传感器.将一条短链DNA通过AuS键自组装固定在电极表面, ATP的核酸适配体与该短链DNA杂交而结合在电极表面.带负电的DNA通过静电吸引结合电解液中的六氨合钌(RuHex)阳离子.当传感器和靶分子ATP孵育后,ATP与核酸适配体结合,使适配体链从电极表面解离,电极表面吸附的DNA量减少,结合RuHex的量随之降低.通过计时库仑技术检测RuHex响应信号降低的量 ,可以对ATP进行定量测定.此传感器的电化学响应信号与ATP浓度对数值呈线性关系,线性检测范围为0.001~100 μmol/L,检出限(S/N=3)为0.5 nmol/L.此传感器检测靶分子ATP后,可以通过简单的操作步骤再生,再生5次后的响应信号为初始信号的90%以上.采用此传感器检测大鼠脑透析液中ATP的含量为(19.2±3.7) nmol/L (n=3).

A Reusable Chronocoulometric Aptamer Sensor for Detection of Adenosine Triphosphate

A reusable chronocoulometric adenosine triphosphate (ATP)-aptamer sensor was developed in this work.A short chain of DNA marked as cDNA containing complementary sequence was immobilized on gold electrode based on Au-S self-assembly.The ATP aptamer was hybridized with cDNA.The surface-confined DNA could bind with Ru(NH3)63+ (RuHex) in the electrolyte via electrostatic interaction.Upon target ATP binding, the aptamer confined onto electrode surface was disassociated from the cDNA oligonucleotides into the solution.Such surface density change of DNA lead to the decrease of chronocoulometric signal for the RuHex which confined on the electrode surface.The chronocoulometric signals showed a linear relationship with logrithm of ATP concentration in the range of 1 nmol/L to 100 μmol/L, and the detection limit of this aptamer sensor could reach 0.5 nmol/L (S/N=3).This aptamer sensor could be regenerated 5 times by simple steps.With this aptamer sensor, the basal level of ATP in the brain cortex micorodialysate was determined to be 19.2±3.7 nmol/L (n=3).