基于石墨烯氧化物-DNA传感器对汞离子高灵敏检测的研究

发布时间：2018-04-18 08:00

本文选题：石墨烯氧化物 + 汞离子　；参考：《江苏大学》2017年硕士论文

【摘要】：汞离子(Hg~(2+))是环境污染中的重要因素之一,由于该物质低浓度即可对动植物带来不可逆的影响,经过循环过程离子浓度被不断富集,对人类的身体健康造成不可估量的伤害。Hg~(2+)可以与特异性核酸序列,如多T的DNA序列作用,引起DNA构型发生变化,基于这个原理一些检测方法被发展,但仍然存在的一些问题:有的方法检测样本少、有的假阳性信号率高、有的灵敏性较低等,为解决这些问题,将Hg~(2+)特异作用的DNA作为识别元件结合石墨烯氧化物(GO)构建生物传感器。生物传感器是分子生物学的一种研究工具,基于生物传感器对Hg~(2+)进行检测,发展检测的新方法与新技术,进行以下几个方面的研究:1.GO表面固定多T序列对汞离子的检测。多T的DNA序列作为识别元件,羧基荧光素(FAM)修饰的DNA序列固定到作为淬灭剂的GO表面,去除没有结合上的DNA,减少了假阳性对检测的影响,提高检测的灵敏性,检测极限为9.37 nM,比物理吸附降低了20%。进一步通过与检测序列互补的DNA序列进行双氨基固定,双氨基修饰的DNA检测极限为2.52 nM,降低了75%。2.双荧光标记多T序列对汞离子的检测。用FAM和SBRY Green I两种荧光染料对DNA序列标记,这两种荧光基团协同作用,相互促进。单氨基修饰的DNA序列结合双荧光修饰构建的传感器检测极限为0.53nM,双氨基修饰的DNA检测极限为0.43 nM,降低了20%。3.硫代磷酸化(PS)修饰的DNA序列固定到GO表面对汞离子检测。Hg~(2+)能特异性切割PS修饰的DNA,使Hg~(2+)能够重复使用,用FAM标记的PS修饰的DNA固定在GO表面对Hg~(2+)检测的极限为1.37 nM,比物理吸附法降低了22%。4.硫代磷酸化修饰的DNA序列结合生物芯片对汞离子的检测。将多个DNA序列样品在玻片上进行点阵排列,加入Hg~(2+)实现对多样品的检测。GO表面物理吸附PS修饰的DNA序列的检测极限为3.187 nM,固定PS修饰的DNA序列的检测极限为0.79 nM。通过上述研究,解决现有Hg~(2+)检测方法中存在的问题,发展了几种Hg~(2+)检测的新方法与新技术,推动食品安全中重金属检测技术的进一步发展。
[Abstract]:Mercury ion (HG) is one of the important factors in environmental pollution. Because the low concentration of the substance can bring irreversible effects on animals and plants, the ion concentration is continuously enriched through the cycle process.Can act with specific nucleic acid sequences, such as polyT DNA sequences, causing changes in the configuration of DNA. Based on this principle, some detection methods have been developed.But there are still some problems: some methods to detect small samples, some false positive signal rate, some low sensitivity, to solve these problems,The biosensor was constructed by using Hg~(2 (DNA) as recognition element and graphene oxide (GOG).Biosensor is a research tool in molecular biology. The detection of Hg~(2 based on biosensor and the development of new methods and techniques are studied in the following aspects: 1. The detection of mercury ions by multi-T sequences fixed on the surface of go.The polyT DNA sequence was used as the recognition element, and the carboxyfluorescein modified DNA sequence was immobilized to the surface of go as a quenching agent to remove the unbound DNA, thus reducing the influence of false positive on the detection and improving the sensitivity of the detection.The detection limit is 9.37 nm, which is 20% lower than physical adsorption.Further, the DNA sequence complementary to the detection sequence was immobilized with two amino groups. The detection limit of the DNA modified by the double amino group was 2.52 nm, which reduced the detection limit by 75. 2.Detection of mercury ions by double fluorescence labeling multiple T sequences.The FAM and SBRY Green I fluorescent dyes were used to label the DNA sequence. The two fluorescent groups acted synergistically and promoted each other.The detection limit of single amino modified DNA sequence combined with double fluorescence modification was 0.53 nm and the detection limit of double amino modified DNA was 0.43 nm, which decreased 20.3 nm.Thiophosphorylated DNA sequence immobilized on go surface to detect mercury ions. Hgf2) can specifically cleave PS modified DNA so that Hg~(2) can be reused.The detection limit of DNA modified with PS modified by FAM on go surface is 1.37 nm, which is 22. 4% lower than that of physical adsorption method.Thiophosphorylation modified DNA sequence combined with biochip to detect mercury ions.The detection limit of PS modified DNA sequence is 3.187 nm and the detection limit of fixed PS modified DNA sequence is 0.79 nm.Through the above research, the problems existing in the existing Hg~(2) detection methods are solved, and several new methods and technologies of Hg~(2) detection are developed to promote the further development of heavy metal detection technology in food safety.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q503;TP212

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