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基于Au-MoS2 纳米复合物的DNA 传感器检测Hg2+研究

发表时间:2017-12-29  浏览量:1325  下载量:156
全部作者: 杜晓丽,康天放
作者单位: 北京工业大学环境与能源工程学院
摘 要: 使用富含胸腺嘧啶(thymine,T)的DNA,基于T-Hg2+-T 结合的高特异性和辣根过氧化物酶(horseradish peroxidase,HRP)及MoS2纳米片对方波伏安(square wave voltammetry,SWV)峰电流信号的催化放大作用,构建用于检测Hg2+的新型电化学DNA生物传感器。制备Au-MoS2纳米复合物,并将其修饰到玻碳电极(glassy carbon electrode,GCE)表面,基于巯基在Au 纳米粒子(Au nanoparticles,Au NPs)表面的化学吸附作用,使巯基修饰的DNA 探针1(DNA1)固定于GCE表面。以巯基修饰的DNA 探针2(DNA2)、Au NPs和HRP制成HRP-Au-DNA2复合物,利用Hg2+与这两条富含胸腺嘧啶的DNA 探针链发生特异性错配形成双链DNA(dsDNA),将HRP 固定在GCE 上,用HRP和MoS2纳米片催化对苯二酚(HQ)与H2O2氧化还原反应产生的方波伏安峰电流作为检测Hg2+的信号。结果表明,在优化的实验条件下,方波伏安峰电流在Hg2+浓度为1.0×10−9~1.0×10−6 mol/L的范围内随Hg2+浓度的增大而线性增大,检测限为1×10−10 mol/L. 同时考察该传感器的稳定性和选择性,并将此传感器用于实际水样中Hg2+的检测,结果满意。
关 键 词: 环境化学;DNA 生物传感器;Hg2+;MoS2;辣根过氧化物酶
Title: Study on Hg2+ determination by DNA sensors based on Au-MoS2 nanocomposites
Author: DU Xiaoli, KANG Tianfang
Organization: College of Environmental and Energy Engineering, Beijing University of Technology
Abstract: Thymine (T)-rich DNA was used to fabricate a novel electrochemical DNA biosensor for Hg2+ determination based on the high specificity of T-Hg2+-T combination and the amplification of the peak current signal of square wave voltammetry (SWV) by horseradish peroxidase (HRP) and MoS2 nanosheets. Au-MoS2 nanocomposites were prepared. The composites were modified onto the surface of glassy carbon electrode (GCE) and thiol-modified DNA probe 1 (DNA1) was also immobilized on the surface of GCE based on the chemisorption of thiols on the surface of Au nanoparticles (Au NPs). Thiol-modified DNA probe 2 (DNA2), Au NPs and HRP were used to prepare HRP-Au-DNA2 composites. The specific mismatch of Hg2+ with thymines of the two probes of thymine-rich single-stranded DNA to produce double strand DNA (dsDNA) was used to immobilize HRP onto the GCE surface. The peak current of SWV produced by the redox reaction between hydroquinone (HQ) and H2O2 catalyzed by the immobilizing HRP and MoS2 nanosheets was used as the signal of Hg2+ determination. The results showed that under the optimal experimental conditions the peak current of SWV increased linearly with the increase of the logarithmic values of Hg2+ concentration over the range of 1.0×10−9-1.0×10−6 mol/L with a detection limit of 1×10−10 mol/L. The stability and selectivity of the sensor were also investigated. The sensor was applied in the determination of Hg2+ in real water samples and satisfactory results were obtained.
Key words: environmental chemistry; DNA biosensors; Hg2+; MoS2; horseradish peroxidase
发表期数: 2017年12月第24期
引用格式: 杜晓丽,康天放. 基于Au-MoS2 纳米复合物的DNA 传感器检测Hg2+研究[J]. 中国科技论文在线精品论文,2017,10(24):2679-2687.
 
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