基于多功能纳米探针的三种电化学免疫传感器的研究

发布时间：2018-04-26 12:49

本文选题：电分析化学 + 电化学免疫传感器　；参考：《西北大学》2017年硕士论文

【摘要】：电化学免疫传感器不仅具有免疫分析的特异性,还具有电分析化学简便、灵敏等优势,能将抗原-抗体相互作用信息转化为易测的电信号,已成为电分析化学最热门的研究领域之一。纳米材料的飞速发展,不仅为抗体/抗原在电极表面的固载提供了良好的基体,还可通过多功能纳米探针为高灵敏电化学免疫传感器的构建提供新颖的信号放大策略,从而改善免疫传感器的分析性能。本文构建了三种基于多功能纳米探针的新型电化学免疫传感器,分别用于人免疫球蛋白(IgG)和癌胚抗原(CEA)的检测,并得到了较好的分析性能,具体工作如下:(1)基于金、银纳米簇的电化学免疫传感器。该传感器利用银纳米簇固载抗体,金纳米簇标记二抗并作为晶核诱导银纳米粒子生成,然后进行电化学还原二次增强银的沉积,借助沉积银的电氧化信号达到定量检测CEA的目标。在优化实验条件下,该免疫传感器的线性范围是0.01pg·mL-1～100 ng·mL-1,检出限为1 fg·mL-1。与其他一些基于金、银纳米粒子的传感器相比,该免疫传感器利用超小尺寸的纳米粒子(纳米簇)固载和标记抗体,提高了抗体的有效利用率;通过金纳米簇对AgN03原位还原和电化学还原双重作用来放大信号,提高了传感器的灵敏度。(2)基于多功能银纳米探针与Fe304磁性纳米粒子的免标记电化学免疫传感器。该传感器通过将固载抗体的Fe304磁性纳米粒子吸引到预先电沉积了银纳米粒子的磁性电极上构建而成。沉积在电极表面的银纳米粒子不但增强了界面导电性,而且可作为电化学探针提供信号源;Fe304磁性纳米粒子不仅可通过氨基化处理负载大量抗体,还能利用其与磁性电极之间的磁力将抗体固定在电极表面。在最优实验条件下,以IgG作为目标分析物,该免疫传感器的线性范围为0.1 pg·mL-1～1.0 μg·mL-1,检出限为0.05 pg·mL-1。该传感器无需使用第二抗体,并且在构建过程中利用了电沉积、磁性作用和化学交联等固定方法,很大程度上保证了传感器的稳定性。(3)基于金纳米棒的电荷标记型电化学免疫传感器。金纳米棒表面通过巯基试剂自组装实现电荷标记和负载二抗的功能。以碳纳米管和壳聚糖复合物(CNTs-Chit)为基底将癌胚抗原抗体交联在基体电极表面,通过夹心型免疫反应在电极表面组装上金纳米棒,利用Fe(CN)63-的电化学氧化还原信号研究界面静电作用对电化学免疫传感器分析性能的影响。金纳米棒大的比表面积为荷负电(功能)分子的修饰和抗体的固定提供了平台。在优化实验条件下,该免疫传感器检测CEA的线性范围为1 fg·mL-1～100ng·mL_1,检出限为0.1fg·mL_1。该传感器旨在探索通过电荷标记构建高灵敏电化学免疫传感器的可能,从研究结果来看,传感界面的静电作用有助于改善免疫传感器的分析性能。该传感器相比其他基于Fe(CN)63-氧化还原信号的电化学免疫传感器具有较低的检出限。
[Abstract]:Electrochemical immunosensor not only has the specificity of immunological analysis, but also has the advantages of simple and sensitive electroanalytical chemistry, which can transform the information of antigen-antibody interaction into electrical signals that are easy to measure. It has become one of the hottest research fields in electroanalytical chemistry. The rapid development of nanomaterials not only provides a good substrate for the immobilization of antibodies / antigens on the electrode surface, but also provides novel signal amplification strategies for the construction of highly sensitive electrochemical immunosensors through multifunctional nano-probes. In order to improve the analytical performance of the immunosensor. In this paper, three novel electrochemical immunosensors based on multifunctional nanoprobes were constructed for the detection of human immunoglobulin (IgG) and carcinoembryonic antigen (CEA). Electrochemical immunosensor for silver nanoclusters. The sensor uses silver nanoclusters to immobilize antibodies and gold nanoclusters to label the second antibody and act as nuclei to induce the formation of silver nanoparticles, and then electrochemical reduction secondary enhancement of silver deposition. The target of quantitative detection of CEA is achieved by electrooxidation signal of deposited silver. Under the optimized experimental conditions, the linear range of the immunosensor was 0.01pg mL-1~100 ng mL -1, and the detection limit was 1fg mL -1. Compared with other sensors based on gold and silver nanoparticles, the immunosensor uses ultrasmall nanoparticles (nanoclusters) to immobilize and label antibodies, thus increasing the effective utilization rate of antibodies. In order to amplify the signal through the dual action of gold nanoclusters on AgN03 in situ reduction and electrochemical reduction, the sensitivity of the sensor is improved. The sensor is based on multifunctional silver nanoparticles and Fe304 magnetic nanoparticles. The sensor was constructed by attracting the Fe304 magnetic nanoparticles loaded with antibodies onto the magnetic electrode where silver nanoparticles were pre-deposited. The silver nanoparticles deposited on the electrode surface not only enhance the interfacial conductivity, but also provide a signal source for Fe304 magnetic nanoparticles, which can not only support a large number of antibodies through amination treatment. The antibody can also be immobilized on the surface of the electrode using the magnetic force between it and the magnetic electrode. Under the optimal experimental conditions, the linear range of the immunosensor was 0.1 PG mL-1~1.0 渭 g mL -1 and the detection limit was 0.05 PG mL -1 with IgG as the target analyte. The sensor does not need to use a second antibody and uses electrodeposition, magnetic interaction and chemical crosslinking in the construction process. The stability of the electrochemical immunosensor based on gold nanorods is largely guaranteed. The surface of gold nanorods can be labeled with charge and loaded with second antibody by self-assembly of thiol reagents. The carcinoembryonic antigen antibody was cross-linked on the surface of the matrix electrode using CNTs-Chit-based carbon nanotube and chitosan complex as the substrate. The gold nanorods were assembled on the electrode surface by sandwich immunoreaction. The effect of interface electrostatic action on the analytical performance of electrochemical immunosensor was studied by using the electrochemical redox signal of Fegna CNN 63-. The large specific surface area of gold nanorods provides a platform for the modification of charged (functional) molecules and the fixation of antibodies. Under the optimized experimental conditions, the linear range of CEA detected by the immunosensor was 1fg mL-1~100ng mLS _ 1, and the detection limit was 0.1fg mL _ 1. The aim of the sensor is to explore the possibility of constructing a highly sensitive electrochemical immunosensor by charge labeling. The results show that the electrostatic action of the sensing interface can improve the analytical performance of the immunosensor. Compared with other electrochemical immunosensors based on Fegna CNC 63-redox signal, the detection limit of this sensor is lower than that of other electrochemical immunosensors.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TP212.2

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