基于Ag@Au纳米棒的电化学免疫传感器的研究
发布时间：2018-09-04 16:32
【摘要】：电化学免疫传感器将免疫反应的特异性与电分析快速、灵敏等优势有机结合,已成为电分析化学最热门的研究领域之一。纳米材料的发展不仅为生物活性单元在电极表面的固载提供了良好的基体,而且为新型电化学免疫传感器的构建提供了许多新颖的构思和策略。Ag@Au纳米棒是一种核壳型金银合金材料,具有稳定性高、比表面积大、催化活性高、生物相容性好等特点。本论文制备了Ag@Au纳米棒,用紫外-可见光谱、透射电镜和X射线衍射图谱等对其进行了表征,并构建了三种基于Ag@Au纳米棒的电化学免疫传感器,具体工作如下：(1)构建了一个基于Ag@Au纳米棒的夹心型电化学免疫传感器。该传感器利用碳纳米纤维-PAMAM复合材料借助戊二醛交联将捕获抗体固定在玻碳电极表面,当目标蛋白存在时,借助夹心型免疫复合物形成将标记在二抗上的Ag@Au纳米棒定量引入电极表面,然后利用纳米棒上Ag的电氧化信号进行检测。碳纳米纤维-PAMAM复合材料不仅可以提供大量的氨基提高抗体的固载量,而且能够显著增强Ag的电氧化信号。在优化实验条件下,以人免疫球蛋白(IgG)为模型目标物,该免疫传感器的线性范围为1fg·mL~(-1)～1000pg·mL~(-1),检出限为0.5fg·mL~(-1)。与经典的银增强免疫传感相比,该传感器利用了Ag@Au纳米棒的“预置入式”银的电氧化信号,免去了银沉积过程。(2)构建了一个基于Ag@Au纳米复合材料的夹心型电化学免疫传感器。通过多巴胺自聚过程将Ag@Au纳米棒负载在四氧化三铁磁性微球上制备了Ag@Au-Fe_3O_4纳米复合材料。利用碳纳米纤维-壳聚糖(CNFs-Chit)复合膜将捕获抗体固载在电极表面,当目标蛋白存在时,借助夹心型免疫复合物的形成将标记在二抗上的Ag@Au-Fe_3O_4定量引入电极表面。利用循环伏安法研究了不同纳米材料修饰电极对H_2O_2的电催化还原,与Fe_3O_4纳米微球和Ag@Au纳米棒修饰电极相比,Ag@Au-Fe_3O_4纳米复合材料修饰电极表现出更强的电催化活性。在优化实验条件下,以Ag@Au-Fe_3O_4纳米复合材料标记二抗构建的免疫传感器检测IgG的线性范围是0.1pg·mL~(-1)～5μg·mL~(-1),检出限为50fg·mL~(-1)。利用该传感器检测血清中IgG,回收率是94.6-106.1%。与基于辣根过氧化物酶的免疫传感器相比,该传感器利用Ag@Au-Fe_3O_4纳米材料作为过氧化物模拟酶,具有更高的化学稳定性。(3)构建了一个基于Ag@Au-CNFs-Chit纳米复合材料的双信号非标记型癌胚抗原电化学免疫传感器。使用直接混合法将Ag@Au纳米棒与碳纳米纤维-壳聚糖(CNFs-Chit)混合并修饰在电极表面,将癌胚抗原抗体固定在此修饰电极表面,利用免疫复合物形成引起Ag电氧化信号或复合材料修饰电极催化H_2O_2还原信号的降低实现目标蛋白癌胚抗原的检测。循环伏安法研究表明：CNFs-Chit纳米复合材料同样能够增强Ag@Au上.Ag的电氧化信号：并且,Ag@Au-CNFs-Chit纳米复合材料修饰电极对H_2O_2还原的电催化活性优于Ag@Au和CNFs-Chit修饰电极,这归功于CNFs-Chit良好的导电性及其与Ag@Au纳米棒的协同催化作用。在最优条件下,该传感器采用两种信号检测癌胚抗原的线性范围分别是0.01pg·mL~(-1)～1ng·mL~(-1)和0.01pg·mL~(-1)～10ng·mL~(-1),检出限为1fg·mL~(-1)。该传感器不仅比夹心型传感器节省时间,而且分析性能优于许多夹心型传感器。
[Abstract]:Electrochemical immunosensor has become one of the most popular research fields in Electroanalytical chemistry, which combines the specificity of immune reaction with the advantages of rapid and sensitive electroanalysis. The development of nanomaterials not only provides a good substrate for the immobilization of bioactive units on the electrode surface, but also provides a new type of electrochemical immunosensor. Ag@Au nanorods are core-shell gold-silver alloy materials with high stability, large specific surface area, high catalytic activity and good biocompatibility. In this paper, Ag@Au nanorods were prepared and characterized by UV-Vis spectroscopy, transmission electron microscopy and X-ray diffraction. Three kinds of electrochemical immunosensors based on Ag@Au nanorods were designed and fabricated as follows: (1) A sandwich electrochemical immunosensor based on Ag@Au nanorods was constructed. Carbon nanofibers-PAMAM composites can not only provide a large number of amino acids to increase the immobilization of antibodies, but also significantly enhance the electrooxidation signal of Ag. Under the condition of human immunoglobulin (IgG) as the model target, the linear range of the immunosensor is 1 FG (-1) to 1 000 PG (-1) and the detection limit is 0.5 FG (-1). Compared with the classical silver enhanced immunosensor, the sensor utilizes the "pre-placed" silver electrooxidation signal of Ag @ Au nanorods, eliminating the silver deposition process. A sandwich electrochemical immunosensor based on Ag@Au nanocomposites was constructed. Ag@Au-Fe_3O_4 nanocomposites were prepared by dopamine self-polymerization of Ag@Au nanorods onto magnetic ferric oxide microspheres. In the presence of protein, Ag @Au-Fe_3O_4 labeled on the second antibody was quantitatively introduced into the electrode surface by the formation of sandwich immune complex. The electrocatalytic reduction of H_2O_2 on different nano-materials modified electrode was studied by cyclic voltammetry. Compared with Fe_3O_4 nano-microspheres and Ag @Au nanorod modified electrode, Ag @Au-Fe_3O_4 nanocomposite was repaired. Under the optimum conditions, the linear range of IgG detection using Ag @Au-Fe_3O_4 nanocomposite labeled antibody was 0.1 PG (-1) ~ 5 UG (-1) and the detection limit was 50 FG (-1). The recovery of IgG in serum was 94.6 (-106.1%) and that based on horseradish radish. Compared with peroxidase immunosensor, Ag @Au-Fe_3O_4 nano-material has higher chemical stability. (3) A double-signal non-labeled carcinoembryonic antigen electrochemical immunosensor based on Ag @Au-CNFs-Chit nano-composite was constructed. Ag @Au nanorods were prepared by direct mixing method. Carcinoembryonic antigen (CEA) antibodies were immobilized on the surface of the modified electrode by mixing with carbon nanofibers-chitosan (CNFs-Chit) and modifying it. The target protein CEA was detected by cyclic voltammetry. CNFs-Chit nanocomposites can also enhance the electro-oxidation signal of Ag on Ag@Au.Moreover, the electro-catalytic activity of Ag@Au-CNFs-Chit nanocomposites modified electrode for H_2O_2 reduction is better than that of Ag@Au and CNFs-Chit modified electrode, which is attributed to the good conductivity of CNFs-Chit and its synergistic catalytic effect with Ag@Au nanorods. The linear range of CEA detection with two signals is 0.01 PG (-1) ~ 1ng (-1) and 0.01 PG (-1) ~ 10NG (-1), respectively. The detection limit is 1 FG (-1). The sensor not only saves time than the sandwich sensor, but also has better analytical performance than many sandwich sensors.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.1
本文编号：2222728
[Abstract]:Electrochemical immunosensor has become one of the most popular research fields in Electroanalytical chemistry, which combines the specificity of immune reaction with the advantages of rapid and sensitive electroanalysis. The development of nanomaterials not only provides a good substrate for the immobilization of bioactive units on the electrode surface, but also provides a new type of electrochemical immunosensor. Ag@Au nanorods are core-shell gold-silver alloy materials with high stability, large specific surface area, high catalytic activity and good biocompatibility. In this paper, Ag@Au nanorods were prepared and characterized by UV-Vis spectroscopy, transmission electron microscopy and X-ray diffraction. Three kinds of electrochemical immunosensors based on Ag@Au nanorods were designed and fabricated as follows: (1) A sandwich electrochemical immunosensor based on Ag@Au nanorods was constructed. Carbon nanofibers-PAMAM composites can not only provide a large number of amino acids to increase the immobilization of antibodies, but also significantly enhance the electrooxidation signal of Ag. Under the condition of human immunoglobulin (IgG) as the model target, the linear range of the immunosensor is 1 FG (-1) to 1 000 PG (-1) and the detection limit is 0.5 FG (-1). Compared with the classical silver enhanced immunosensor, the sensor utilizes the "pre-placed" silver electrooxidation signal of Ag @ Au nanorods, eliminating the silver deposition process. A sandwich electrochemical immunosensor based on Ag@Au nanocomposites was constructed. Ag@Au-Fe_3O_4 nanocomposites were prepared by dopamine self-polymerization of Ag@Au nanorods onto magnetic ferric oxide microspheres. In the presence of protein, Ag @Au-Fe_3O_4 labeled on the second antibody was quantitatively introduced into the electrode surface by the formation of sandwich immune complex. The electrocatalytic reduction of H_2O_2 on different nano-materials modified electrode was studied by cyclic voltammetry. Compared with Fe_3O_4 nano-microspheres and Ag @Au nanorod modified electrode, Ag @Au-Fe_3O_4 nanocomposite was repaired. Under the optimum conditions, the linear range of IgG detection using Ag @Au-Fe_3O_4 nanocomposite labeled antibody was 0.1 PG (-1) ~ 5 UG (-1) and the detection limit was 50 FG (-1). The recovery of IgG in serum was 94.6 (-106.1%) and that based on horseradish radish. Compared with peroxidase immunosensor, Ag @Au-Fe_3O_4 nano-material has higher chemical stability. (3) A double-signal non-labeled carcinoembryonic antigen electrochemical immunosensor based on Ag @Au-CNFs-Chit nano-composite was constructed. Ag @Au nanorods were prepared by direct mixing method. Carcinoembryonic antigen (CEA) antibodies were immobilized on the surface of the modified electrode by mixing with carbon nanofibers-chitosan (CNFs-Chit) and modifying it. The target protein CEA was detected by cyclic voltammetry. CNFs-Chit nanocomposites can also enhance the electro-oxidation signal of Ag on Ag@Au.Moreover, the electro-catalytic activity of Ag@Au-CNFs-Chit nanocomposites modified electrode for H_2O_2 reduction is better than that of Ag@Au and CNFs-Chit modified electrode, which is attributed to the good conductivity of CNFs-Chit and its synergistic catalytic effect with Ag@Au nanorods. The linear range of CEA detection with two signals is 0.01 PG (-1) ~ 1ng (-1) and 0.01 PG (-1) ~ 10NG (-1), respectively. The detection limit is 1 FG (-1). The sensor not only saves time than the sandwich sensor, but also has better analytical performance than many sandwich sensors.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.1
【参考文献】
相关期刊论文 前1条
1 李建平;高会玲;熊志刚;;磁性纳米金共价固定癌胚抗原单克隆抗体的电流型免疫传感器[J];高等学校化学学报;2008年11期
，本文编号：2222728
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2222728.html
教材专著
