【作者】 李鑫；

【导师】 邹强；

【作者基本信息】 天津大学 ， 海洋环境科学与技术， 2018， 硕士

【摘要】 汞离子(Hg²⁺)和铅离子(Pb²⁺)是对人体危害非常大的重金属离子,即使在超低浓度下也会对人体健康有多种危害。水中的汞和铅可以通过食物链进入人体,特别是通过水产品。海水中微量的重金属离子通过食物链富集作用也会对人体造成巨大的损伤。因此,在海水的复杂环境中建立能够特异性识别、高灵敏度和低检测限（LOD）的重金属离子检测方法对人体乃至整个生物链都有着巨大的作用。本文提出了利用表面增强拉曼（SERS）技术的方法来实现海水中汞离子和铅离子的痕量检测,并且LOD测试结果比传统的汞离子检测方法理想,如8×10^-1111 g/mL（酶联免疫吸附法）,9×10^-1010 g/mL（冷原子荧光法）,1.6×10^-66 g/mL（氢化物发生原子吸收法）,4×10^-1010 g/mL（电热原子吸收法测速）,与其它方法相比,本文的结果表明本系统对Hg²⁺和Pb²⁺的检测具有很好的敏感性。（1）SERS芯片固态基底制备如同人类的指纹一样,每个物质也都具有其独特的拉曼光谱,因此SERS技术也被广泛的运用于诸多领域,实现了对化学生物分子等的检测。在SERS技术的运用过程中,一个结构合理,性能稳定的基底起着至关重要的作用。因此本文讨论了通过不同方式制备不同结构的基底并对其性能进行检测分析。（2）汞离子检测SERS固态芯片传感器的构建及应用本文利用胸腺嘧啶（T）和2-萘硫醇（2-NT）修饰金纳米粒子（AuNPs）,采用寡核苷酸功能化纳米传感器和SERS芯片,建立了SERS分析Hg²⁺离子的平台。采用2-NT作为拉曼信号分子,T碱基能与Hg²⁺离子形成T-Hg-T结构,使纳米粒子吸附在SERS芯片上。在实验中,获得了DNA和2-NT的最佳实验浓度,计算出平均每个AuNP上附着960个DNA分子。LOD为1.0 ppt(1.0×10^-12g/mL),远远低于世界卫生组织规定的饮用水10 ppb（10μg/L）的限制。该传感器具有检测成本低、样品前处理简单、处理方法环保和减少假阳性等优点。最后采用该纳米传感器测定了海水中痕量的Hg²⁺,其结果准确。（3）汞铅离子同时检测SERS固态芯片传感器及新型分子逻辑门电路的构建本文利用DNA酶对金属离子的依赖性,构造了一类用于Hg²⁺和Pb²⁺离子同时检测的DNA逻辑门。为了灵敏、特异地检测Hg²⁺和Pb²⁺离子,利用寡核苷酸功能化和金包覆的聚苯乙烯微球（PSMPs）建立了SERS活性平台。在这项工作中,Hg²⁺和Pb²⁺作为输入,SERS信号作为输出。Hg²⁺离子被T-Hg-T桥捕获,Pb²⁺离子与8-17 DNA酶结合,破坏裂解链。Hg²⁺的LOD为0.1 nM,Pb²⁺的LOD为1.0 nM,远远低于世界卫生组织规定的饮用水中分别对汞离子和铅离子的LOD10ppb（31 nM）和10 ppm（3.02×10⁴ nM）。该系统有可能成为智能DNA计算器设计应用的理想候选者。此外,所设计的概念还可以推广到可与DNA分子结合的其他多重金属离子,并应用于环境检测、毒素检测和液体分析等许多其它领域。更多还原

【Abstract】 Mercury ion(Hg²⁺)and lead ion(Pb²⁺)are very harmful heavy metal ions to human bodies.Even at ultra-low concentration,they can cause a variety of hazards to human health.Mercury and lead in water can enter human bodies through food chain,especially aquatic products.Heavy metal ions in seawater can also cause huge damage to human bodies through the enrichment of food chain.Therefore,the establishment of a specific,sensitive and low detection limit（LOD）heavy metal ion detection method in the complex environment of seawater plays a huge role of human body and even the whole biological chain.In this paper,three methods of surface enhanced Raman（SERS）technique are introduced for the trace detection of mercury and lead ions in seawater.The test results are much better than traditional Hg²⁺ions detection methods,such as 8×10^-1111 g/mL by ELISA,9×10^-1010 g/mL by CA-AFS,1.6×10^-66 g/mL by HGAAS,4×10^-10g/mL by ETAAS.Compared with other methods,our results have excellent sensitivity to Hg²⁺and Pb²⁺detection.（1）Preparation of solid substrate for SERS chipLike humans’fingerprints,each substance has its own unique Raman spectra,so SERS technology has been widely used in many fields to achieve the detection of chemical and biological molecules.In the application of SERS technology,a base with reasonable structure and stable performance plays a vital role.Therefore,the substrates with different structural properties were discussed and their properties were examined.（2）Construction and application of SERS solid state chip sensor for mercury ion detectionA surface-enhanced Raman scattering platform for the selective trace analysis of Hg²⁺ions was reported based on ploy-thymine（T）aptamer/2-naphthalenethiol（2-NT）-modified gold nanoparticles（AuNPs） which was Oligonucleotide-Functionalized nanosensor and SERS chip.2-NT was used as a Raman reporter and T aptamer can form a T-Hg²⁺-T structure with Hg²⁺ions,making SERS nanosensor absorbed to the SERS chip.The optimum concentration of DNA and 2-NT was obtained.An average of 960 DNA molecules attached to each AuNP were measured.The limit of detection（LOD）is 1.0 ppt（1.0×10^-1212 g/mL）,which is far below the limit of 10.0 ppb for drinking water stipulated by the World Health Organization.The sensor has the advantages of low detection cost,simple sample pretreatment,green solution and reducing false positive.Furthermore,the nanosensor was used for the determination of trace Hg²⁺in the water of lake,and a reliable result has been obtained accurately.（3）Simultaneous detection of mercury and lead ions by SERS solid-state chip sensor and construction of new molecular logic gate circuitA conceptually new class of DNA logic gates for Hg²⁺and Pb²⁺ions simultaneous detection has been constructed based on the activity of DNAzyme dependent on metal ions.For sensitive and specific detection of Hg²⁺and Pb²⁺ions,we demonstrate a surface-enhanced Raman scattering-active platform by employing the oligonucleotide-functionalized and gold coated polystyrene microspheres（PSMPs）.In this work,Hg²⁺and Pb²⁺were used as the input,and the SERS signals were the output.Hg²⁺ions were captured by a mismatched T-Hg-T bridge.Pb²⁺ions were bound to 8-17 DNAzyme to break the cleavage substrate.The LOD of Hg²⁺is0.1 nM and Pb²⁺is 1.0 nM,which is far below the limit of 10.0 ppb（31 nM）and 10.0ppm（3.02×10⁴ nM）for drinking water stipulated by the World Health Organization.Additionally,this system has the potential to be ideal candidates for intelligent DNA calculator design applications.Furthermore,the designed strategy could be extended to other multiplex metal ions that can be combined with DNA molecules,and can be applied to many other fields such as environmental detection,toxin detection and liquid analysis.更多还原