Herein, a sensitive electrochemical Pb²⁺ sensor was developed which based on DNA‐functionalized Au nanoparticles(AuNPs) and nanocomposite modified electrode. The DNA‐functionalized AuNPs includes two types of DNA, namely a Pb²⁺‐mediated DNAzyme comprising a biotin labeled‐enzyme DNA and a substrate strand DNA with a typical stem‐loop structure, and a ferrocene‐labeled linear signal DNA. Without Pb²⁺, the hairpin loop impeded biotin binding to avidin on the electrode. However,when the goal Pb²⁺ exists, the substratum strand was divided into two fragments that lead to the enzyme strand was substratumed on the electrode and biotin was admited by avidin, bringing about DNA‐functionalized AuNP(AuNPs) deposition on the electrode surface.The differential pulse voltammetry (DPV) was used to measure electrochemical response signals connect to signal DNA.For the amplification characters of the DNA‐functionalized AuNPs and nanocomposite, the electrochemical detection signal of Pb²⁺ was greatly improved and revealed high specificity. Under optimum conditions, the resultant biosensor bringed out a high sensitivity and selectivity for the determination of Pb²⁺. The proposed method was able to detect as low as picomolar Pb²⁺ concentrations.

中文翻译：

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铅阳离子双信号放大电化学生物传感器

在此，基于DNA功能化的金纳米颗粒（AuNPs）和纳米复合修饰电极开发了一种灵敏的电化学Pb ²⁺传感器。经DNA官能化的AuNPs包括两种类型的DNA，即Pb ²⁺介导的DNAzyme，其包含生物素标记的酶DNA和具有典型茎环结构的底物链DNA，以及二茂铁标记的线性信号DNA。没有Pb ^2+时，发夹环会阻止生物素与电极上的抗生物素蛋白结合。但是，当目标Pb ²⁺存在时，将基底链分成两个片段，导致酶链在电极上被基底化，生物素被抗生物素蛋白吸收，使DNA功能化的AuNP（AuNPs）沉积在电极表面上。差分脉冲伏安法（DPV） DNA官能化的AuNPs和纳米复合材料的扩增特性，大大提高了Pb ²⁺的电化学检测信号，并显示出高特异性。在最佳条件下，所得生物传感器对Pb ²⁺的测定具​​有很高的灵敏度和选择性。所提出的方法能够检测低至皮摩尔的Pb ²⁺浓度。