基于G-四联体门控制效应的铅离子适配体传感器  

Electrochemical Lead Ion Aptasensor Based on G-Quadruplex and Gate-controlled Signal Amplification

作　　者：邓欢[1] 孙觅[1] 魏小平[1] 黎洪增 李建平[1] 

机构地区：[1]广西岩溶地区水污染控制与用水安全保障协同创新中心,广西电磁化学功能物质重点实验室,桂林理工大学化学与生物工程学院,桂林541004

出　　处：《分析化学》2016年第6期888-892,共5页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金资助项目(No.21375031);广西自然科学基金创新研究团队项目(No.2015GXNSFFA139005)资助~~

摘　　要：将富鸟嘌呤(G)序列核酸适配体与门控制效应相结合,通过控制门的开关实现信号放大,构建了新型电化学生物传感器,用于铅离子(Pb^(2+))的高灵敏检测。首先将单-6-巯基-β-环糊精(6-SH-β-CD)自组装在金电极上,形成有序排列的分子自组装膜,且分子之间留有空隙,可作为探针通过的门结构。随后将发夹结构的富含G序列的核酸适配体修饰在环糊精次面端口,制得可特异性识别Pb^(2+)的电化学生物传感器。富G序列适配体结合Pb^(2+)后可折叠形成G-四联体结构(G4-Pb^(2+)),覆盖住电极表面的探针通道,产生关门效应,使探针氧化还原电流强度减小,进而形成门控制效应,利用该效应可进行Pb^(2+)的定量检测。门控制效应显著提高了信噪比和检测的灵敏度,在1×10^(-13)~5×10^(-11)mol/L浓度范围内,Pb^(2+)浓度的负对数与DPV响应电流呈良好的线性关系,检出限为3.6×10^(-14)mol/L(DL=3δ_b/K)。传感器用于实际水样品中Pb^(2+)的测定,结果令人满意。A new strategy for constructing electrochemical aptasensor for lead ion （ Pb2＋ ） analysis with extremely high sensitivity was proposed based on the formation of G-quadruplex （G4） when Pb2＋ reacting with G-rich aptamers, and the gate-controlled effect was achieved through the controllable channels of probe. SH-β-cyclodextrins were firstly self-assembled on the surface of gold electrode to form an ordered monomolecular layer containing interspaces among β-CD units. When the G-rich aptamer was linked to the self-assembledβ-CD and the sensor was immersed into the Pb2＋ solution, the aptamers would combine with Pb2＋ and then form G-quadruplex structures, which would cover the interspaces and then block the channels for probe entrance. The whole process reduced the oxidative current of probe, which provided a fundamental basis of Pb2＋determination in a quantitative way. Gate-controlled effect enhanced signal-to-noise ratio as well as sensitivity simultaneously. The differential pulse voltammetry response current showed a good linear relationship with the negative logarithm of Pb2＋ concentration in the range from 1×10-13 mol/ L to 5×10-11 mol/ L, with a detection limit of 3. 6×10-14 mol/ L（DL = 3δb / K）. The aptasensor was successfully applied to the detection of Pb2＋ in real water samples with recoveries of 97. 5% -103. 3% .

关 键 词：电化学传感器 门控制 G-四联体 二价铅离子 

分 类 号：X832[环境科学与工程—环境工程] TP212.3[自动化与计算机技术—检测技术与自动化装置]