A dual-signal readout enzyme-free immunosensor based on hybridization chain reaction-assisted formation of copper nanoparticles for the detection of microcystin-LR

文献类型： 外文期刊

第一作者： He, Zuyu

作者： He, Zuyu;Cai, Yue;Liu, Weipeng;Liu, Yingju;He, Zuyu;Yang, Ziming;Li, Puwang;Lei, Hongtao

作者机构：

关键词： Immunoassay; Dual-signal readout; Hybridization chain reaction; Microcystin-LR

期刊名称：BIOSENSORS & BIOELECTRONICS （ 影响因子：10.618； 五年影响因子：9.323 ）

ISSN： 0956-5663

年卷期： 2019 年 126 卷

页码：

收录情况： SCI

摘要： Enzyme-based electrochemical biosensors are widely used in immunoassays, but the intrinsic disadvantages of enzymes including instability or sensitivity to temperature and pH should be considered. Herein, an enzyme-free and dual-signal readout immunoassay was established to detect microcystin-LR (MC-LR) sensitively and selectively. Firstly, the microplate was modified with gold nanoparticles-decorated-carbon nanotubes (AuNP-CNT) to immobilize sufficient antigens by the high surface area of CNT and high affinity of AuNP. Then, silver nanoparticles were decorated on gold nanorods to form corn-like AgNP/AuNR composite and then capture secondary antibody and initiator DNA strand. After hybridization chain reaction, long double helix DNA strands can be formed on AgNP/AuNR to germinate copper nanoparticles. A dual-signal readout from the current responses of both silver and copper ions was obtained by using differential pulse stripping voltammetry with the aid of acid treatment, By using a competitive immunoreaction, MC-LR can be detected in a linear range from 0.005 mu g/L to 20 mu g/L with a lower detection limit of 2.8 mu g/L. The reproducibility, stability and specificity were all acceptable, indicating its promising application in environment monitoring and sensitive electrochemical detection for other analytes.

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