基于Ag@Au納米棒的電化學(xué)免疫傳感器的研究
發(fā)布時(shí)間：2018-09-04 16:32
【摘要】：電化學(xué)免疫傳感器將免疫反應(yīng)的特異性與電分析快速、靈敏等優(yōu)勢有機(jī)結(jié)合,已成為電分析化學(xué)最熱門的研究領(lǐng)域之一。納米材料的發(fā)展不僅為生物活性單元在電極表面的固載提供了良好的基體,而且為新型電化學(xué)免疫傳感器的構(gòu)建提供了許多新穎的構(gòu)思和策略。Ag@Au納米棒是一種核殼型金銀合金材料,具有穩(wěn)定性高、比表面積大、催化活性高、生物相容性好等特點(diǎn)。本論文制備了Ag@Au納米棒,用紫外-可見光譜、透射電鏡和X射線衍射圖譜等對其進(jìn)行了表征,并構(gòu)建了三種基于Ag@Au納米棒的電化學(xué)免疫傳感器,具體工作如下：(1)構(gòu)建了一個(gè)基于Ag@Au納米棒的夾心型電化學(xué)免疫傳感器。該傳感器利用碳納米纖維-PAMAM復(fù)合材料借助戊二醛交聯(lián)將捕獲抗體固定在玻碳電極表面,當(dāng)目標(biāo)蛋白存在時(shí),借助夾心型免疫復(fù)合物形成將標(biāo)記在二抗上的Ag@Au納米棒定量引入電極表面,然后利用納米棒上Ag的電氧化信號進(jìn)行檢測。碳納米纖維-PAMAM復(fù)合材料不僅可以提供大量的氨基提高抗體的固載量,而且能夠顯著增強(qiáng)Ag的電氧化信號。在優(yōu)化實(shí)驗(yàn)條件下,以人免疫球蛋白(IgG)為模型目標(biāo)物,該免疫傳感器的線性范圍為1fg·mL~(-1)～1000pg·mL~(-1),檢出限為0.5fg·mL~(-1)。與經(jīng)典的銀增強(qiáng)免疫傳感相比,該傳感器利用了Ag@Au納米棒的“預(yù)置入式”銀的電氧化信號,免去了銀沉積過程。(2)構(gòu)建了一個(gè)基于Ag@Au納米復(fù)合材料的夾心型電化學(xué)免疫傳感器。通過多巴胺自聚過程將Ag@Au納米棒負(fù)載在四氧化三鐵磁性微球上制備了Ag@Au-Fe_3O_4納米復(fù)合材料。利用碳納米纖維-殼聚糖(CNFs-Chit)復(fù)合膜將捕獲抗體固載在電極表面,當(dāng)目標(biāo)蛋白存在時(shí),借助夾心型免疫復(fù)合物的形成將標(biāo)記在二抗上的Ag@Au-Fe_3O_4定量引入電極表面。利用循環(huán)伏安法研究了不同納米材料修飾電極對H_2O_2的電催化還原,與Fe_3O_4納米微球和Ag@Au納米棒修飾電極相比,Ag@Au-Fe_3O_4納米復(fù)合材料修飾電極表現(xiàn)出更強(qiáng)的電催化活性。在優(yōu)化實(shí)驗(yàn)條件下,以Ag@Au-Fe_3O_4納米復(fù)合材料標(biāo)記二抗構(gòu)建的免疫傳感器檢測IgG的線性范圍是0.1pg·mL~(-1)～5μg·mL~(-1),檢出限為50fg·mL~(-1)。利用該傳感器檢測血清中IgG,回收率是94.6-106.1%。與基于辣根過氧化物酶的免疫傳感器相比,該傳感器利用Ag@Au-Fe_3O_4納米材料作為過氧化物模擬酶,具有更高的化學(xué)穩(wěn)定性。(3)構(gòu)建了一個(gè)基于Ag@Au-CNFs-Chit納米復(fù)合材料的雙信號非標(biāo)記型癌胚抗原電化學(xué)免疫傳感器。使用直接混合法將Ag@Au納米棒與碳納米纖維-殼聚糖(CNFs-Chit)混合并修飾在電極表面,將癌胚抗原抗體固定在此修飾電極表面,利用免疫復(fù)合物形成引起Ag電氧化信號或復(fù)合材料修飾電極催化H_2O_2還原信號的降低實(shí)現(xiàn)目標(biāo)蛋白癌胚抗原的檢測。循環(huán)伏安法研究表明：CNFs-Chit納米復(fù)合材料同樣能夠增強(qiáng)Ag@Au上.Ag的電氧化信號：并且,Ag@Au-CNFs-Chit納米復(fù)合材料修飾電極對H_2O_2還原的電催化活性優(yōu)于Ag@Au和CNFs-Chit修飾電極,這歸功于CNFs-Chit良好的導(dǎo)電性及其與Ag@Au納米棒的協(xié)同催化作用。在最優(yōu)條件下,該傳感器采用兩種信號檢測癌胚抗原的線性范圍分別是0.01pg·mL~(-1)～1ng·mL~(-1)和0.01pg·mL~(-1)～10ng·mL~(-1),檢出限為1fg·mL~(-1)。該傳感器不僅比夾心型傳感器節(jié)省時(shí)間,而且分析性能優(yōu)于許多夾心型傳感器。
[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.
【學(xué)位授予單位】：西北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：O657.1
本文編號：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.
【學(xué)位授予單位】：西北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：O657.1
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 李建平;高會玲;熊志剛;;磁性納米金共價(jià)固定癌胚抗原單克隆抗體的電流型免疫傳感器[J];高等學(xué)�；瘜W(xué)學(xué)報(bào);2008年11期
，本文編號：2222728
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