A label-free electrochemical biosensor based on magnetic biocomposites with DNAzyme and hybridization chain reaction dual signal amplification for the determination of Pb2+,Microchimica Acta

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A label-free electrochemical biosensor based on magnetic biocomposites with DNAzyme and hybridization chain reaction dual signal amplification for the determination of Pb2+
Microchimica Acta ( IF 5.3 ) Pub Date : 2020-09-24 , DOI: 10.1007/s00604-020-04548-5
Chenyuan Weng ₁ , Xiaoyun Li ₁ , Qiaoyun Lu ₁ , Wei Yang ₁ , Jing Wang ₁ , Xiaoqiang Yan ₁ , Bingzhi Li ₂ , Marwan Sakran ₁ , Junli Hong ₁ , Wanying Zhu ₁ , Xuemin Zhou ₁

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A highly sensitive and selective electrochemical biosensor for Pb2+ with a dual-amplification strategy is proposed. The first amplification step was realized by the cycle of Pb2+ and 8–17 DNAzyme (S2), and the hybridization chain reaction (HCR) triggered by S1 further amplified the electrochemical signal. Fe3O4@Au NPs, as a multifunctional magnetic carrier, is not only manifested in the construction of a magnetically controlled electrochemical response interface, but also has significant contribution in the purifying system, reducing interference, increasing the specific surface area, and the DNA loading. The magnetic nanocomposites were characterized by TEM as spheres with particle size of around 39 nm. When there was no Pb2+, long double-strand DNA (dsDNA) is formed on the surface of Fe3O4@Au NPs by the S1-triggered HCR; in the presence of Pb2+, S2 is activated and S1 on the surface of magnetic biocomposites (Fe3O4@Au NPs-S1) is continuously cleaved with the cycle of Pb2+ and S2, leading to a significant decrease of methylene blue (MB) absorbed on dsDNA. Such reverse dual-signal amplification strategy effectively increased the current difference and improved the sensitivity of the proposed sensor. The electrochemical signal of MB was obtained by differential pulse voltammetry (DPV) with preconcentration, showing a linear response toward Pb2+ ranging from 50 pM to 1 μM with a detection limit of 15 pM. The proposed method has feasible applications in detecting other heavy metal ions based on other metal-dependent DNAzyme. Graphical Abstract Graphical Abstract

中文翻译：

基于DNA酶和杂交链反应双信号放大磁性生物复合材料的无标记电化学生物传感器测定Pb2+

提出了一种具有双放大策略的高灵敏度和选择性的 Pb2+ 电化学生物传感器。第一个扩增步骤是通过 Pb2+ 和 8-17 DNAzyme (S2) 的循环实现的，S1 触发的杂交链反应 (HCR) 进一步放大了电化学信号。Fe3O4@Au NPs作为一种多功能磁性载体，不仅表现在磁控电化学响应界面的构建上，而且在净化系统、减少干扰、增加比表面积和DNA负载等方面也有显着贡献。磁性纳米复合材料通过 TEM 表征为粒径约为 39 nm 的球体。当没有 Pb2+ 时，S1 触发的 HCR 在 Fe3O4@Au NPs 表面形成长双链 DNA（dsDNA）；在 Pb2+ 存在下，S2 被激活，磁性生物复合材料 (Fe3O4@Au NPs-S1) 表面上的 S1 随着 Pb2+ 和 S2 的循环不断裂解，导致 dsDNA 上吸收的亚甲蓝 (MB) 显着减少。这种反向双信号放大策略有效地增加了电流差并提高了所提出的传感器的灵敏度。MB 的电化学信号是通过差分脉冲伏安法 (DPV) 获得的预浓缩，显示出对 Pb2+ 的线性响应，范围为 50 pM 至 1 μM，检测限为 15 pM。所提出的方法在基于其他金属依赖性脱氧核糖核酸酶检测其他重金属离子方面具有可行的应用。图形摘要图形摘要这种反向双信号放大策略有效地增加了电流差并提高了所提出的传感器的灵敏度。MB 的电化学信号是通过差分脉冲伏安法 (DPV) 获得的预浓缩，显示出对 Pb2+ 的线性响应，范围为 50 pM 至 1 μM，检测限为 15 pM。所提出的方法在基于其他金属依赖性脱氧核糖核酸酶检测其他重金属离子方面具有可行的应用。图形摘要图形摘要这种反向双信号放大策略有效地增加了电流差并提高了所提出的传感器的灵敏度。MB 的电化学信号是通过差分脉冲伏安法 (DPV) 获得的预浓缩，显示出对 Pb2+ 的线性响应，范围为 50 pM 至 1 μM，检测限为 15 pM。所提出的方法在基于其他金属依赖性脱氧核糖核酸酶检测其他重金属离子方面具有可行的应用。图形摘要图形摘要所提出的方法在基于其他金属依赖性脱氧核糖核酸酶检测其他重金属离子方面具有可行的应用。图形摘要图形摘要所提出的方法在基于其他金属依赖性脱氧核糖核酸酶检测其他重金属离子方面具有可行的应用。图形摘要图形摘要

更新日期：2020-09-24

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