纳米通道适配体传感器对马拉硫磷的检测

准确快速检测水体中农药残留对水体安全至关重要。基于纳米通道电流整流现象,利用适配体特异性结合目标物的特点,构建了电化学适配体传感器,以实现马拉硫磷(Mal)的检测.通过金硫键将Mal适配体1(Apt-1)修饰到镀有金膜的纳米管腔内,利用Mal与Apt-1和适配体2(Apt-2)特异性结合后改变纳米通道内电荷密度的特点,实现Mal的定量检测.采用扫描电镜(SEM)和圆二色谱(CD),对纳米管及通道内部进行表征;对Apt-1在纳米通道内部的修饰浓度、Apt-2的使用浓度、孵育溶液的pH以及孵育时间进行优化.在最佳工作条件下,Mal浓度的对数与传感器的响应电流信号呈线性关系,传感器对Mal的检测线性范围为1.0×10^-8~1.0×10^-6 mol/L,检测限(LOD)为3.33×10^-9 mol/L.考察了传感器的稳定性以及对Mal的检测选择性,并将传感器用于水样中Mal的分析,所得结果与气相色谱(GC)方法所得结果基本一致.

Detection of Malathion by nanochannel aptamer sensor

Accurate and rapid detection of pesticide residues in water is crucial to water safety. Based on the current rectification phenomenon of nanochannels, and combined with the characteristics of aptamers that specifically binding to the target, an electrochemical aptamer sensor was constructed to realize the detection of malathion(Mal). The Mal aptamer 1(Apt-1)was modified into the gold-coated nanopipette lumen through gold-sulfur bonds, and the specific binding of Mal to Apt-1 and apta-mer 2(Apt-2)was used to change the interior of the nanochannel. The characteristics of charge density enable the quantitative detection of Mal. Scanning electron microscopy(SEM)and circular dichroism(CD)were used to characterize the nanopipettes and the inside of the nanochannel. The experimental parameters such as the modification concentration of Apt-1, the concentration of Apt-2, and the pH of the incubation solution and the incubation time were optimized. Under the optimum experimental conditions, the logarithm of Mal concentration is linear with the response current signal of the sensor, and linear range of Mal detection range of the sensor is 1.0×10^-8-1.0×10^-6 mol/L, and the limit of detection(LOD)was 3.33×10^-9 mol/L. The stability of the aptamer sensor and the selectivity of Mal detection were investigated. The sensor can be used for the analysis of Mal in water samples, and the results obtained are basically consistent with those obtained by gas chromatography(GC).