基于纳米金银修饰的免疫球蛋白和甲胎蛋白免疫电极的研究

发布时间：2018-10-24 20:42

【摘要】：电流及电位型电化学免疫传感器是将免疫分析技术与电化学传感器相结合的一种新的免疫分析方法,是基于测量电流、电位变化来进行免疫分析的生物传感器。抗原或抗体在敏感膜上的结合或继后的反应引起电流、电极电位或膜电位发生改变,而且这种变化与待测物浓度之间存在线性关系。与其它免疫传感技术相比,该方法具有灵敏、快速、成本低、携带方便,操作简单、易数字化、能方便地实现实时输出和检测。免疫球蛋白G(IgG)是人体血清中含量最高的抗体,占血清中免疫球蛋白的70～80%,是唯一能通过胎盘的免疫球蛋白,具有抗菌、抗病毒、抗毒素的特性,在机体免疫防护中起着重要作用。正常人血清中的甲胎蛋白(AFP)含量在20ng/mL以下,如果血液中AFP呈现较高浓度,往往是几种恶性病如精原细胞癌、原发性肝癌的的重要特征之一,此外,一些患有非癌疾病如毛细管扩张失调、遗传酪氨酸血症、急性病毒性肝炎、肝硬化等的病人也观察到AFP浓度有上升的现象。AFP已经成为临床检验上的一项重要指标。研究IgG和AFP的检测方法具有重要的理论意义和实际意义。本文利用纳米金、纳米银材料,采用多种电极材料,运用包埋、沉积、吸附等手段固定抗体,直接测定抗原与抗体反应前后的电流、电位变化,主要内容如下: 1.利用滴涂于铂盘表面的Nafion膜中负电性的磺酸基与anti-IgG分子中的氨基阳离子之间的静电作用实现抗体的结合,同时通过负电性的纳米金增加抗体的固定量,最后在修饰电极的表面涂敷一层明胶(Gelatin)薄膜进行固定,制成Gelatin/anti-IgG/Au/Nafion/Pt膜,制得非标记免疫传感器。用循环伏安法(CV)和交流阻抗法(Nyquist)对电极逐层修饰过程进行了表征,并对免疫传感器的性能进行了研究。该传感器测定lgG的最低浓度为2.0ng/mL,标准曲线的线性范围在5～960ng/mL,回归方程为:AE=-2.2+31.7log[IgG],响
[Abstract]:Current and potential type electrochemical immunosensor is a new immunosensor which combines immunoassay technique with electrochemical sensor. It is a biosensor based on measuring the changes of current and potential. The binding of antigen or antibody on the sensitive membrane or the subsequent reaction caused the change of current, electrode potential or membrane potential, and there was a linear relationship between the change and the concentration of the substance to be measured. Compared with other immunosensor techniques, this method is sensitive, fast, low cost, easy to carry, easy to operate, easy to digitize, and can easily realize real-time output and detection. Immunoglobulin G (IgG) is the highest antibody in human serum, accounting for 70% of the immunoglobulin in the serum. It is the only immunoglobulin that can pass through the placenta. It has the characteristics of antibacterial, antivirus and antitoxin. It plays an important role in immune protection. The content of alpha-fetoprotein (AFP) in normal human serum is below 20ng/mL. If the concentration of AFP in blood is higher, it is often one of the important characteristics of several malignant diseases such as spermatogonia and primary liver cancer. Some patients with non-cancerous diseases such as capillary dilatation, hereditary tyrosinemia, acute viral hepatitis, liver cirrhosis and other patients also observed that the concentration of AFP has increased. AFP has become an important index in clinical tests. It is of great theoretical and practical significance to study the detection methods of IgG and AFP. In this paper, we use nano-gold, nano-silver, various electrode materials, entrapping, depositing, adsorption and other means to fix the antibody, and directly determine the changes of current and potential before and after the reaction of antigen and antibody. The main contents are as follows: 1. The binding of the antibody was realized by electrostatic interaction between the negatively charged sulfonic acid group in the Nafion film coated on the platinum-disk surface and the amino cation in the anti-IgG molecule, and the fixed amount of the antibody was increased through the negative electrically charged nanocrystalline gold. Finally, a gelatin (Gelatin) film was coated on the surface of the modified electrode to make a Gelatin/anti-IgG/Au/Nafion/Pt film, and an unlabeled immunosensor was prepared. The electrode layer modification process was characterized by cyclic voltammetry (CV) and alternating current impedance (Nyquist), and the performance of the immunosensor was studied. The minimum concentration of lgG measured by the sensor is 2.0 ng / mL, and the linear range of the standard curve is 5 ~ 960ng / mL. The regression equation is: AE=-2.2 31.7log [IgG], ring.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2006
【分类号】：R392

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