Target-inspired Pb2+-dependent DNAzyme for ultrasensitive electrochemical sensor based on MoS2-AuPt nanocomposites and hemin/G-quadruplex DNAzyme as signal amplifier
Target-inspired Pb2+-dependent DNAzyme for ultrasensitive electrochemical sensor based on MoS2-AuPt nanocomposites and hemin/G-quadruplex DNAzyme as signal amplifier
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DOI：
10.1016/j.bios.2019.111560
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发表时间：
2019-11-01
影响因子：
12.6
通讯作者：
Li, Chaorui
中科院分区：
文献类型：
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作者：
Ji, Renyue;Niu, Wuceng;Li, Chaorui
本研究利用MoS2-AuPt纳米材料和hemin/ g -四联DNAzyme作为电催化信号标签，开发了一种Pb2+电化学DNAzyme传感器，用于水环境中铅离子（Pb2+）的超灵敏检测。链霉亲和素（SA）修饰的氧化锡功能化还原氧化石墨烯(rGO-SnO2) /金纳米颗粒（AuNPs）作为传感器平台，可增强电导率并固定化更多Pb2+特异性DNAzyme。在Pb2+存在下，Pb2+依赖性DNAzyme与Pb2+特异性反应，将底物链（SS）切割成两个自由片段，并在电极上释放生物素修饰酶链（Bio-ES）。将富含G-DNA （G-DNA）链标记的MoS2-AuPt纳米复合材料与通过辅助DNA暴露的Bio-ES连接，并加入血红蛋白形成血红蛋白/ g -四重体，生物传感器实现了信号放大。电流信号主要来自于MoS2-AuPt纳米复合材料和血红素/ g四联体对H2O2的共催化还原。在最佳条件下，所设计的生物传感器对Pb2+的检测灵敏度在0.1 pg mL（-1）至1000 ng mL（-1）之间，最低检测限为38 fg mL(-1)（基于3 σ）。该生物传感器具有超灵敏和特异性，代表了水环境中Pb2+检测的潜在应用。
In this work, a novel Pb2+ electrochemical DNAzyme sensor was developed for ultrasensitive detection of lead ions (Pb2+) in water environment by coupling with the MoS2-AuPt nanomaterials and hemin/G-quadruplex DNAzyme, which acting as the electrocatalytic signal tag. Streptavidin (SA) modified tin dioxide-functionalized reduced graphene oxide (rGO-SnO2) /gold nanoparticles (AuNPs) served as a sensor platform for enhancing conductivity and immobilizing more Pb2+-specific DNAzyme. In the presence of Pb2+, the Pb2+-dependent DNAzyme specifically reacted with Pb2+, cleaving the substrate strand (SS) into two free fragment and releasing the biotin-modified enzyme strand (Bio-ES) on the electrode. Connecting MoS2-AuPt nanocomposites labeled with G-rich DNA (G-DNA) strand and exposure of Bio-ES through the Helper DNA, as well as adding hemin to form a hemin/G-quadruplex, the biosensor achieved signal amplification. Chronoamperometry was used to record the current signal, which was primarily derived from the cocatalysis reduction of H2O2 by MoS2-AuPt nanocomposites and the hemin/G-quadruplex. Under optimal conditions, the designed biosensor exhibited sensitive detection of Pb2+ from 0.1 pg mL(-1) to 1000 ng mL(-1), with a lower detection limit of 38 fg mL(-1) (based on 3 sigma). This proposed biosensor is ultrasensitive and specific, representing a potential application for the detection of Pb2+ in a water environment.