石墨烯基电化学传感器构建及其对疾病标志物和食品安全的检测

发布时间：2018-05-03 14:46

本文选题：石墨烯 + 电化学传感器　；参考：《郑州大学》2016年硕士论文

【摘要】：目前,纳米材料中应用最广泛的材料之一是二维石墨烯材料。由于石墨烯具有优异的电气性能、电化学性能、光学性能、结构特性和机械性能,在环境监测、药物检测、食品分析和生物医学等方面都有广泛的应用。此外,石墨烯表面易于通过共键或者非共键的方式将检测目标物的识别元素功能化,以达到增强其灵敏性、特异性、承载能力和生物相容性等目的,使其在各领域中的应用性更强。本论文简单论述了石墨烯材料、电化学传感器以及石墨烯电化学生物传感器的研究进展,并基于此开展以下研究内容:(一)阿尔茨海默病(AD),是老年痴呆症中最常见的类型。β-淀粉样蛋白(Aβ)已经被认为是阿尔茨海默病的重要标志物,体液中Aβ的检测将促进AD的早期诊断。基于抗体与抗原的特异性结合和核酸适配体的识别作用,我们构建了一种高灵敏检测Aβ_(1-42)寡聚体的类免疫型传感器。首先,在羧基化氧化石墨烯修饰的电极表面通过NHS和EDC活化作用进行Aβ_(1-42)寡聚体的抗体固定,并用牛血清白蛋白进行封闭。其次,采用一种简单的方法制备核酸适配体-Au-硫堇(Th)的共轭物作为信号指标。当加入Aβ_(1-42)寡聚体时,由于抗体和适配体均可以与Aβ_(1-42)寡聚体结合,形成“三明治”类型的结构,从而引起Th峰电流的变化。在最佳实验条件下,对不同浓度的Aβ_(1-42)寡聚体进行检测。实验结果表明,Th峰电流变化量与Aβ_(1-42)寡聚体的含量呈现良好的线性关系,其线性范围为0.2~25mM(相关系数为0.995),检测限为45 nM(S/N=3)。此外,制备的传感器也成功用于脑脊髓液中Aβ_(1-42)寡聚体含量的测定。这为阿尔茨海默病的早期诊断提供了新的策略。(二)β_(2)-兴奋剂作为生长促进剂,常被添加到饲料中提高动物的生长速率、减少脂肪量和增加肌肉质量,俗称为“瘦肉精”。盐酸克伦特罗(CLB)和沙丁胺醇(SAL)是β_(2)-兴奋剂中最重要的两种物质,它们的检测在食品安全方面显得尤为重要。采用石墨烯和Nafion复合膜(GN-Nafion膜)修饰玻碳电极(GCE)构筑灵敏的电化学传感器,同时测定CLB和SAL。在0.04 M的BR缓冲液中,CLB和SAL在GN-Nafion/GCE上均出现了一对明显的氧化还原峰。并且,两者氧化峰电位差值约200 mV,这使得GN-Nafion/GCE能够实现同时检测CLB和SAL。CLB和SAL检测限分别为0.13μM和0.11μM(S/N=3)。并将该传感器用于猪肉中CLB和SAL的同时检测,得到了高的准确度和好的回收率。此外,所构筑的电极显示出了优异的重现性、稳定性和选择性。(三)双酚A(BPA)常被用于制造婴儿奶瓶、矿泉水瓶、医疗器械及食品包装袋等,其安全性问题成为了公众关注的焦点。检测BPA的含量对人类的医疗保健具有重要意义。基于血红素和石墨烯修饰电极,构筑了一种简单的电化学传感器用于特异性检测BPA。血红素通过π-π作用固定在石墨烯修饰电极上;当测定BPA时,由于血红素可以与BPA形成氢键,从而实现了对其高灵敏性检测。在最佳实验条件下,该传感器的线性范围为0.2~10mM(相关系数0.996),检测限为67 nM(S/N=3)。此外,使用该传感器对食品包装袋中的BPA进行测定,也取得了满意的结果。该传感器为食品安全方面BPA的检测提供了一种快速、简单的新方法。
[Abstract]:At present, one of the most widely used materials in nanomaterials is two-dimensional graphene materials. Due to the excellent electrical properties, electrochemical properties, optical properties, structural properties and mechanical properties, graphene has extensive applications in environmental monitoring, drug detection, food analysis and biomedicine. In addition, the surface of graphene is easy to pass through In order to enhance its sensitivity, specificity, bearing capacity and biocompatibility, the recognition element of the target object is functionalized by common bond or non common bond to enhance its application in various fields. This paper briefly discusses the study of graphene materials, electrochemical sensors and graphene electrochemical biosensors. Progress, and based on this study: (1) Alzheimer's disease (AD) is the most common type of Alzheimer's disease. Beta amyloid (A beta) has been considered an important marker of Alzheimer's disease, and the detection of A beta in body fluids will promote early diagnosis of AD. We have constructed a highly sensitive A beta (1-42) oligomer like immunosensor. First, the antibody of A beta (1-42) oligomers was immobilized on the surface of the carboxylated graphite oxide modified electrode through the activation of NHS and EDC and sealed with bovine serum albumin. Secondly, a simple method was used to prepare the nucleic acid. The conjugate of the aptamer -Au- thio (Th) is a signal indicator. When the A beta (1-42) oligomer is added, the antibody and the aptamer can be combined with the A beta (1-42) oligomer to form a "sandwich" type structure, thus causing the change of the peak current of the Th. Under the best experimental strip, the test of the A beta (1-42) oligomer with different concentrations is tested. The results show that the Th peak current change has a good linear relationship with the content of A beta (1-42) oligomer, with a linear range of 0.2~25mM (correlation coefficient 0.995) and a detection limit of 45 nM (S/N=3). In addition, the prepared sensor is also used to determine the content of A beta (1-42) oligomer in the brain spinal fluid. This is an early diagnosis of Alzheimer's disease. New strategies are provided. (two) beta (2) - stimulant as a growth promoter, often added to feed to increase the growth rate of animals, reduce fat and increase muscle mass, commonly known as "lean meat essence". CLB and SAL are the most important substances in beta (2) - stimulants, their detection in food safety It is particularly important to use graphene and Nafion composite membrane (GN-Nafion film) modified glassy carbon electrode (GCE) to construct a sensitive electrochemical sensor. At the same time, a pair of obvious oxidation-reduction peaks appear on CLB and SAL on GN-Nafion/GCE in the BR buffer of 0.04 M, and the difference between the peak potential of oxidation peak is about 200 mV, and this makes the difference of the oxidation peak potential of about 200 mV. GN-Nafion/GCE can detect simultaneous detection of CLB and SAL.CLB and SAL detection limits of 0.13 mu M and 0.11 M (S/N=3). The sensor is used for simultaneous detection of CLB and SAL in pork, and high accuracy and good recovery are obtained. Furthermore, the constructed electrodes show excellent reproducibility, stability and selectivity. (three) bisphenol A (BPA) is often used. It has been used to make baby bottles, mineral water bottles, medical instruments and food packaging bags. The safety problem has become the focus of public attention. The detection of BPA is of great significance for human health care. Based on heme and Shi Moxi modified electrode, a simple electrochemical sensor is constructed to detect the blood red of BPA. specifically. The element is immobilized on the graphene modified electrode through the effect of pi pi. When the BPA is determined, the heme can form a hydrogen bond with BPA, thus achieving its high sensitivity detection. Under the optimum experimental conditions, the linear range of the sensor is 0.2~10mM (correlation coefficient 0.996) and the detection limit is 67 nM (S/N=3). In addition, the sensor is used for food packaging. Satisfactory results were obtained in the determination of BPA in the bag. The sensor provides a fast and simple new method for the detection of BPA in food safety.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.1;TP212

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