基于二维纳米材料构建电化学传感器的研究及应用

发布时间：2018-05-30 16:11

本文选题：二维纳米材料 + 生物传感器　；参考：《济南大学》2017年硕士论文

【摘要】：目前,癌症已经成为危害人类健康的最主要疾病之。以现有的科技水平来看,早期诊断仍然是有效治疗癌症的重要手段。在癌症的早期诊断中,肿瘤标志物是重要的媒介而且已经得到了广泛的应用。无论是在现代实验室还是在临床分析各种化学和生物分子方面,生物传感器都发挥着越来越重要的作用。目前发展各种功能化纳米材料为提高生物传感器的性能提供了一种新的研究思路。尤其是二维纳米材料基生物传感器,它们独特的电子、光学及化学性质,引起了人们研究的兴趣。本文旨在利用二维纳米材料及其复合物的优异性能构建生物传感器,用于肿瘤标志物的检测。本论文的主要研究内容如下:1.制备了稳定均匀的Au@Ag NPs,使其同时具有Au NPs的稳定性和Ag NPs的优异的催化性能。构建了基于Au@Ag NPs与HRP共同标记第二抗体的夹心型电化学免疫传感器。Au@Ag NPs可以提高HRP的催化效率,且本身可以作为类酶放大过氧化氢和对苯二酚的电化学信号。壳聚糖功能化的氮掺杂石墨烯(CS-NG)具有大的比表面积和优良的导电性,作为传感平台可以负载大量第一抗体(Ab1)。通过检测PBS溶液中过氧化氢和对苯二酚的电化学信号变化实现癌胚抗原(CEA)的检测。在最优条件下,CEA的检测范围为0.0001~100 ng mL-1,检出限为0.05 pg mL-1。另外,该免疫传感器具有特异性、重现性高、稳定性强等其它必须的分析性能。2.类石墨氮化碳(g-C3N4)与层状MoS2通过混合煅烧的方法复合,并作为高效的发光材料构建电致发光(ECL)免疫传感器。与g-C3N4相比,制备的g-C3N4/MoS2具有更强更稳定的ECL活性。原因是MoS2的引入,可以促进g-C3N4电子传递、提高电子-空穴的分离效率,克服g-C3N4易钝化的缺点。基于g-C3N4/MoS2的ECL免疫传感器对甲胎蛋白(AFP)具有高的灵敏度,其检测范围为0.001~50 ng mL-1,检出限为0.33 pg m L-1。因此,该免疫传感器在肿瘤诊断方面具有较好的应用前景。3.制备了基于CdS-MoS2纳米复合物和双共反应剂的免标记的ECL免疫传感器,用于检测原降钙素(PCT)。通过一锅煮的水热法制备片状CdS-MoS2纳米复合物,并在ECL免疫传感器中作发光材料。由于大的比表面积和降低的带隙,CdS-MoS2纳米复合物对S2O82-显示出好的电催化还原性,进而产生大量的SO4·-。另外,H2O2的引入可以诱导S2O82-分解为SO4·-。CdS-MoS2纳米复合物和双共反应剂的协同效应可以提高免疫传感器的灵敏度。在最优条件下,该分析方法对PCT具有较高的灵敏度,检测范围为0.0001~10 ng m L-1,检出限为33 fg mL-1。另外,该免疫传感器具有高的特异性、好的重现性和长期的稳定性。4.制备了基于MoS2/Au复合材料的免标记型电化学免疫传感器。传感器以MoS2/Au复合材料为基底材料,H2O2为电化学探针,通过抗原-抗体免疫反应前后电流的变化检测甲胎蛋白(AFP)。AuNPs的优异的导电性和生物相容性,及MoS2对H2O2优异的催化性能等优点,能够显著提高免疫传感器的稳定性和灵敏度。在最优条件下,该分析方法对AFP具有较高的灵敏度,检测范围为0.005~50 ng m L-1,检出限为2.5 pg m L-1。5.经电还原法处理,MoS2导电性得到极大的增强。沉积一层金属纳米花(AuNFs),可进一步增强导电性和生物相容性。实验结果表明所制备的AuNFs/r MoS2/GCE可以促进铁氰化钾和二茂铁的电子传递。基于rMoS2/AuNFs和外切酶循环放大策略,我们制备了DNA传感器。首先,中间标记二茂铁的发卡DNA(HP)做捕获探针,通过Au-S组装在AuNFs/rMoS2/GCE电极上;当有目标DNA存在时,发卡DNA与目标DNA发生杂化,在3′突出端配对生成双链,继而引发Exo III的剪切过程,释放目标DNA。HP剩余单链特定的互补序列使其进一步生成发卡结构,因而二茂铁靠近电极表面,电化学信号增强。基于二茂铁信号变化,实现目标DNA的灵敏检测。
[Abstract]:At present, cancer has become the most important disease that endangers human health. Early diagnosis is still an important means of effective treatment for cancer. In the early diagnosis of cancer, tumor markers are an important medium and have been widely used, both in modern laboratories and in clinical analysis. Biosensors are playing a more and more important role in various chemical and biological molecules. At present, the development of various functionalized nanomaterials provides a new way of thinking to improve the performance of biosensors. In particular, two dimensional nanomaterial based biosensors have attracted people's unique electronic, optical and chemical properties. The purpose of this paper is to use the excellent performance of two-dimensional nanomaterials and their complexes to construct biosensors for detection of tumor markers. The main contents of this paper are as follows: 1. the stable and uniform Au@Ag NPs is prepared, which has the stability of Au NPs and the excellent catalytic performance of Ag NPs. Based on Au@Ag The sandwich electrochemical immunosensor.Au@Ag NPs, which is co labeled with NPs and HRP,.Au@Ag NPs can improve the catalytic efficiency of HRP and can amplify the electrochemical signal of hydrogen peroxide and hydroquinone as an enzyme. The chitosan functionalized nitrogen doped graphene (CS-NG) has a large specific surface area and excellent conductivity as a sensing platform. A large number of first antibodies (Ab1) can be loaded. By detecting the electrochemical signal changes of hydrogen peroxide and hydroquinone in the PBS solution, the detection of carcinoembryonic antigen (CEA) is realized. Under the optimal condition, the detection range of CEA is 0.0001~100 ng mL-1, the detection limit is 0.05 PG mL-1., and the immunization sensor has the specificity, high reproducibility and strong stability. Other necessary analytical properties.2. graphite nitride (g-C3N4) and layered MoS2 are combined with the method of mixed calcination, and the electroluminescent (ECL) immunosensor is constructed as an efficient luminescent material. Compared with g-C3N4, the prepared g-C3N4/MoS2 has a stronger and more stable ECL activity. The reason is that MoS2 is introduced to promote g-C3N4 electron transfer. The separation efficiency of high electron hole can overcome the disadvantage of g-C3N4 passivation. The g-C3N4/MoS2 based ECL immune sensor has high sensitivity to alpha fetoprotein (AFP), its detection range is 0.001~50 ng mL-1, the detection limit is 0.33 PG m L-1. therefore, the immunosensor has a good prospect of application in tumor diagnosis. A label free ECL immunosensor for the detection of procalcitonin (PCT) by a MoS2 nanocomposite and a bireactive agent. The tablet like CdS-MoS2 nanocomposites were prepared by a one pot hydrothermal method and used as a luminescent material in the ECL immunosensor. The CdS-MoS2 nanocomposites were good for S2O82- due to large specific surface area and reduced band gap. In addition, the introduction of H2O2 can induce the synergistic effect of S2O82- decomposition to SO4. -.CdS-MoS2 nanocomposites and double co reactants, which can improve the sensitivity of the immunosensors. Under optimal conditions, this method has a high sensitivity to PCT, and the detection range is 0.0001~10 ng m L-1. The detection range is 0.0001~10 ng M L-1. The output limit is 33 FG mL-1., and the immunosensor has high specificity, good reproducibility and long-term stability..4. has prepared a marker free electrochemical immunosensor based on MoS2/Au composites. The sensor is based on MoS2/Au composite material and H2O2 as an electrochemical probe. The current changes by the antigen antibody immunoreaction. The excellent conductivity and biocompatibility of alpha fetoprotein (AFP).AuNPs and the excellent catalytic performance of MoS2 to H2O2 can significantly improve the stability and sensitivity of the immune sensor. Under optimal conditions, the analytical method has a high sensitivity to AFP, the detection range is 0.005~50 ng m L-1, and the detection limit is 2.5 PG M L-1.5. The electrical conductivity of MoS2 was greatly enhanced by electro reduction. A layer of metal nanoscale (AuNFs) was deposited to further enhance electrical conductivity and biocompatibility. The experimental results showed that the prepared AuNFs/r MoS2/GCE could promote the electron transfer of potassium ferricyanide and ferrocene. Based on the rMoS2/AuNFs and exonuclease cycle amplification strategy, we prepared DNA sensor. First, the intermediate mark two ferrocene DNA (HP) is a capture probe, which is assembled on the AuNFs/rMoS2/GCE electrode by Au-S; when the target DNA exists, the hairpin DNA is hybridized with the target DNA, and the double chain is formed at the 3 'protruding end, then the shear process of the Exo III is triggered, and the specific complementary sequence of the target DNA.HP remaining single chain is released. The two ferrocene is closer to the surface of the electrode and the electrochemical signal is enhanced. Based on the change of the two ferrocene signal, the sensitive detection of the target DNA is realized.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R730.4;O657.1;TP212

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