磁性纳米粒子的电化学转化及生物传感应用

发布时间：2018-10-07 19:52

【摘要】：纳米粒子电化学开辟了纳米技术新方向并在多个领域展现出诱人前景。纳米复合材料可结合多个组分的性质甚至表现出协同效应,应用广泛,其合成方法和性能开发是前沿和难点。磁性纳米粒子基于独特的磁力学、电学、热学和其它物理/化学性质备受关注,广泛用于分离富集及光致发热治疗肿瘤等领域,但其电化学拓展鲜有报道。基于其本身丰富且优异的性质和功能,结合灵活电化学技术,可望进一步丰富磁性材料的性质,制备多功能磁性纳米复合材料,籍此研制新型生物传感器。在本学位论文中,我们主要综述了电化学生物传感器、磁性纳米粒子和普鲁士蓝的研究进展。在这些基础上,我们在温和环境下采用多种电化学技术转化氧化铁磁性纳米粒子成为高电化学活性和催化性的普鲁士蓝,并结合金共沉积技术制备了普鲁士蓝-金复合材料,籍此研制了以磁性纳米粒子为标记物的三明治型免疫生物传感器和免标记型适体生物传感器,效果满意。主要工作如下:1.开发了中性水相体系中电化学转化Fe2O3磁性纳米粒子(MNPs)成为普鲁士蓝(PB)的新方法并用于生物传感信号放大检测禽流感病毒。在中性的K3Fe(CN)6溶液中,在磁场控制下,金电极表面施加高电位触发电化学析氧形成局部强酸性环境使磁性纳米粒子化学反应释放铁离子;接下来施加低电位电化学还原得到K4Fe(CN)6与铁离子反应生成普鲁士蓝。控制氧化电位和时间可调控普鲁士蓝生成速度及性质。该方法在MNPs的磁性基础上进一步拓展了其电化学,在中性初始环境下进行且空间可控地生成强电化学活性的普鲁士蓝。受此启发,我们进一步开发了以MNPs为标记物的三明治型免疫生物传感器,然后基于电化学转化MNPs标记物生成的PB的电化学性质高效放大信号以灵敏检测禽流感病毒(H5N1)。该生物传感器检测范围为0.0025 HAU-0.16 HAU(5?L样品),检测限为0.00074 HAU,比同类传感器低了1个数量级。2.开发了结合MNPs电化学转化和金电沉积技术的新法制备PB-Au纳米复合物并用于高性能的安培化学传感。首先,通过磁场将MNPs固定在金磁电极表面,在2 m M HAu Cl4,1 m M K3[Fe(CN)6]以及0.1 M K2SO4溶液中,采用开发的电化学转化法获得PB,同时,在低电位过程中,电还原的金与PB均匀混合,最终获得PB-Au复合材料。通过控制前驱体的比例可调控PB-Au纳米复合物的尺寸及形貌。采用扫描电镜技术和多种电化学技术对其形貌、电化学性能及催化性能进行表征并与常规PB修饰电极进行比较。PB-Au纳米材料修饰的电极导电性好、测试稳定性好,对H2O2还原和氧化的催化性能优异,明显优于从常规PB或金纳米粒子修饰电极。PB-Au修饰电极传感H2O2线性检测区间为0.002-5.7m M,灵敏度为934?A·cm-2·m M-1,检测下限低(72 n M),并有优异的操作和储存稳定性。3.基于PB-Au复合膜开发免标记电化学适体生物传感器。基于PB-Au纳米材料的高导电性、协同催化特性及生物亲和性,以及其表面丰富的金结合位点,我们在复合物表面固定巯基修饰适体并用于捕获凝血酶。通过凝血酶对电极表面传质和导电性的影响,以PB的电化学活性和催化活性降低为信号实现灵敏检测。线性检测区间为0.1 n M-100 n M,灵敏度为5.1?A·cm-2·n M-1,检测下限为13 p M。此免标记适体传感器此外展示优良的再现性和稳定性。此外,鉴于其易用性、设计简单、操作便捷,本文提出的方法可以作为一个优异的设计模式用于其他生物传感器的制备。
[Abstract]:Nano-particle electrochemistry opens up a new direction of nanotechnology and exhibits attractive prospects in many fields. Nano-composites can bond multiple components and even show the synergistic effect. It is widely used. Its synthetic methods and performance development are the leading and difficult points. Magnetic nanoparticles have attracted much attention based on unique magnetic mechanics, electrical, thermal and other physical/ chemical properties, widely used in the fields of separation and enrichment and light-induced fever treatment, but their electrochemical development is rarely reported. Based on its abundant and excellent properties and functions, combined with flexible electrochemical technology, it is expected that the properties of magnetic materials can be further enriched, and the multifunctional magnetic nano composite material can be prepared, and the novel biosensor is developed. In this paper, we reviewed the progress of electrochemical biosensor, magnetic nanoparticles and Prussian blue. On these bases, we use a variety of electrochemical techniques to convert ferric oxide magnetic nanoparticles into Prussian blue with high electrochemical activity and catalytic properties in a mild environment, and prepare Prussian blue-gold composite material in combination with gold co-deposition technique. A sandwich immunobiosensor and a non-labeled aptamer biosensor based on magnetic nanoparticles were developed. The main work is as follows: 1. The new method of electrochemically converting Fe2O3 magnetic nanoparticles (MNPs) into Prussian blue (PB) in neutral water phase system was developed and used to amplify and detect the avian influenza virus. In the neutral K3Fe (CN) 6 solution, under the control of the magnetic field, the gold electrode surface is subjected to high potential to trigger electrochemical oxygen evolution to form a locally strong acid environment to cause the magnetic nano-particles to chemically react to release iron ions; and then, a low-potential electrochemical reduction is applied to obtain the K4Fe (CN) 6 and the iron ion to generate Prussian blue. controlling oxidation potential and time can regulate Prussian blue generation speed and property. The method further expands its electrochemistry on the magnetic basis of MNPs, and generates Prussian blue with strong electrochemical activity under a neutral initial environment. Inspired by this, we further developed a sandwich-type immunobiosensor with MNPs as markers, and then efficiently amplified the signal based on the electrochemical properties of PB generated by the electrochemical conversion of MNPs markers to sensitively detect the avian influenza virus (H5N1). The detection range of the biosensor is 0.0025 HAU-0.16HAU (5? L sample), and the detection limit is 0.00074 HAU, which is one order of magnitude lower than that of the same type of sensor. PB-Au nanocomposites were prepared by a new method combining MNPs electrochemical conversion and gold electrodeposition technology and used for high performance Ampere chemical sensing. firstly, MNPs are fixed on the surface of the gold magnetic electrode by a magnetic field, and PB is obtained by adopting the developed electrochemical conversion method in the 2m M HAu Cl4, 1m M K3[Fe (CN) 6] and 0.1M K2SO4 solution, meanwhile, in the low potential process, the electroreduced gold and the PB are uniformly mixed, finally a PB-Au composite material is obtained. the size and the shape of the PB-Au nano composite can be controlled by controlling the proportion of the precursor. The morphology, electrochemical performance and catalytic performance were characterized by scanning electron microscope (SEM) and various electrochemical techniques, and compared with the conventional PB modified electrode. PB-Au nano material modified electrode has good conductivity, good testing stability, excellent catalytic performance for H2O2 reduction and oxidation, and obviously superior to conventional PB or gold nanoparticle modified electrode. The linear detection interval of PB-Au modified electrode was 0. 002-5.7m M, the sensitivity was 934? A 路 cm-2 路 m M-1, the lower limit of detection was low (72n M), and excellent operation and storage stability were obtained. Development-free electrochemical aptamer biosensor based on PB-Au composite film. Based on the high conductivity, co-catalytic properties and biological affinity of PB-Au nano-materials, as well as the gold binding sites with rich surface, we fixed and modified the aptamer on the surface of the complex and used to capture thrombin. By means of the influence of thrombin on the surface mass transfer and conductivity of the electrode, a sensitive detection of the signal is realized with the electrochemical activity and catalytic activity of PB. The linear detection interval is 0. 1 n M-100n M, the sensitivity is 5. 1? A 路 cm-2 路 n M-1, and the lower limit of detection is 13p M. The non-labeled aptamer sensor also exhibits excellent reproducibility and stability. In addition, given its ease of use, simple design and convenient operation, the proposed method can be used as an excellent design pattern for the preparation of other biosensors.
【学位授予单位】：湖南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TP212.3

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