We present a novel simple strategy for the detection of Pb²⁺ based on G-quadruplex DNA and gold nanoparticles. First, gold nanoparticles were chemically adsorbed onto the surface of a thiol-modified gold electrode. Subsequently, the substrate DNA1 was adsorbed onto the surfaces of the gold nanoparticles via thiol–gold bonds, so that the complementary guanine-rich DNA2 could be hybridized to the gold electrode in sequence. [Ru(NH₃)₆]³⁺ (RuHex), which can be electrostatically adsorbed onto the anionic phosphate of DNA, served as an electrochemical probe. The presence of Pb²⁺ can induce DNA2 to form a stable G-quadruplex and fall off the gold electrode. The amount of RuHex remaining on the electrode surface was determined by electrochemical chronocoulometry (CC). The prepared biosensor showed high sensitivity for Pb²⁺ with a linear range with respect to ln(c_Pb2+) from 0.01 to 200 nM and a low detection limit of 0.0042 nM under optimal conditions. Because of the high selectivity of the Pb²⁺-specific DNA2, the designed biosensor also showed low false-positive signal rates with other metal ions in real-world examples. Therefore, this strategy has the potential for practical application in environmental monitoring.

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我们提出了一种新颖的简单策略，用于基于G-四链体DNA和金纳米颗粒检测Pb ²⁺。首先，将金纳米颗粒化学吸附到硫醇修饰的金电极的表面上。随后，底物DNA1通过硫醇-金键被吸附到金纳米颗粒的表面上，这样互补的鸟嘌呤富集DNA2可以与金电极顺序杂交。可以静电吸附到DNA的阴离子磷酸盐上的[Ru（NH ₃）₆ ] ³⁺（RuHex）用作电化学探针。Pb ²⁺的存在可以诱导DNA2形成稳定的G-四链体并从金电极上掉落。残留在电极表面的RuHex量通过电化学计时库仑法（CC）确定。所制备的生物传感器显示出对Pb ^2+的高灵敏度，相对于ln（c _{Pb2 +}）线性范围为0.01至200 nM，并且在最佳条件下的检测限低至0.0042 nM。由于Pb ²⁺特异性DNA2的高选择性，因此在实际示例中，设计的生物传感器还显示出与其他金属离子相比较低的假阳性信号发生率。因此，该策略具有在环境监测中实际应用的潜力。

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