电化学传感器论文：基于电活性纳米复合材料构建生物传感的研究

1、 电化学传感器论文：基于电活性纳米复合材料构建生物传感的研究【中文摘要】生物传感器是目前极为活跃的研究领域,而其中电化学传感器因具有好的选择性、高灵敏度、低成本、分析速度快、操作简单、易于微型化等优点,在环境监测、食品和医药工业、临床诊断等领域有着重要的应用价值。在电化学生物传感器的研制中,因纳米性材料拥有很多优点,比如它具有优越的导电能力、其良好的催化特性及其生物的相容性比较好,所以研究其在电化学传感器中的应用,对于提出新理论和新方法,构造新型、简单的电分析生命传感器具有非常重要的实际意义。同时构建纳米-生物传感界面,将纳米功能材料与生物功能分子的特殊性质及性能相结合,发挥材料间的协同效应,

2、有助于加快生物传感器的发展。本文以纳米和纳米-生物传感界面的构建,以及在电化学传感器中的应用为主旨,期间具体开展的研究工作如下：1.本文通过戊二醛将壳聚糖(CHIT)和电子介体甲苯胺蓝(TB)进行交联,得到的CHIT-TB复合物修饰在金电极(Au)表面,靠静电作用吸附金纳米粒子(AuNPs)。再利用纳米金材料良好的生物兼容性、大的比表面积固定乙肝表面抗体(HBsAb),从而可进一步对乙肝表面抗原进行检测。构建的CHIT-TB/Au NPs/HBsAb/BSA免疫传感器兼具以下优点：CHIT在此不仅可以提供一个良好的生物微环境,同时它通过戊二醛交联,将TB共价键合上去,解决了电子介体易泄漏问题,

3、提高电极的稳定性。Au NPs具有良好的导电性和大的比表面积,对于构建的传感器能起到放大信号作用,能提高该传感器的灵敏度。实验过程中采用微分脉冲伏安法(DPV),对HBsAg进行定量检测。检测的HBsAg的浓度范围在1-200 ng mL-1,检测限为0.28 ng mL-1。该方法检测范围宽、检测限低,从而为肝炎的早期诊断提供了一个方便,快捷,且低成本的方法。2.介绍一种灵敏检测癌症标记物-甲胎蛋白(AFP)的新型电化学免疫传感器,这种传感器用石墨烯作为一个传感平台,金纳米粒子(Au NPs)用于固定a-甲胎蛋白抗体(anti-AFP)。首先,化学【英文摘要】Biosensor is a v

4、ery active research and engineering technical field. Wherein, electrochemical biosensors have valuable applications in clinical diagnosis, environmental monitoring, food and pharmacy industries because of its excellent selectivity, high sensitivity, rapid response, low cost, continuous detection, ea

5、sy to be miniaturized. In the design and fabrication of electrochemical biosensors, given the characteristics of nano-materials such as the ability of facilitating electron transfer rate, catalytic performance, absorbability, application of nano-materials in bio-electroanalysis plays a meaningful ro

6、le, in terms of proposing new detection principles and new detection methods/techniques, as well as developing novel yet sensitive electrochemical biosensors. Construction of nanobio-interface, incorporating the distinctive features of nano-materials and biomolecules to exert a synergistic effect, c

7、ontributes a lot to the development of biosensors. With emphasis on the contruction of nano-films and nano-biomolecule composite interfaces, as well as their application in electrochemical biosensors, this article has carried out the following works:1. A novel amperometric immunosensor has been deve

8、loped by self-assembling gold nanoparticles (Au NPs) onto a toluidine blue-branched chitosan (CHIT-TB) modified electrode for the sensitive determination of hepatitis B surface antigen (HBsAg) as a model protein. The formation of CHIT-TB composite film not only effectively avoids the leakage of TB a

9、nd retains its electrochemical activity, but also enhances the conductivity and charge-transport properties of the composite. Further adsorption of Au NPs into the CHIT matrix provides both the interactive sites for the immobilization of HBsAb and a favorable microenvironment to maintain the activit

10、y of the HBsAb, in addition prevents leakage of HBsAb molecules from the CHIT-TB/Au NPs/HBsAb film structure efficiently. The morphologies and electrochemistry of the formed nanocomposite film were investigated by using scanning electron microscopy and electrochemical techniques including cyclic vol

11、tammetry and electrochemical impedance spectroscopy. The HBsAg concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased voltametric values were proportional to the HBsAg concentration in the range of 1 to 2

12、00 ng mL-1. The detection of HBsAg levels in five sera obtained from hospital showed acceptable accuracy.2. A novel electrochemical immunosensor for sensitive detection of cancer biomarker-fetoprotein (AFP) is described that uses a graphene sheet sensor platform and gold nanoparticles (Au NPs) for i

13、mmobilization of-fetoprotein antibody (anti-AFP). Greatly enhanced sensitivity for the cancer biomarker is based on a dual signal amplification strategy:First, chemically reduced graphene (CRG) functionalized with TB (CRG-TB) is well-dispersed into water through the coulomb repulsion between TB-adso

14、rbed CRG sheets. Meanwhile, functionalized graphene sheets used for the biosensor platform increased the surface area to capture a large amount of antibodies, thus amplifying the detection response. Second, good biocompatibility of Au NPs, which enhances the antibody absorption and promotes electron

15、 transfer between redox mediator and the surface of electrode could maintain antibody activity. Therefore a novel and simple electrochemical immunosensor for the ultrasensitive detection of AFP was developed. The developed immunosensor showed a wide linear ranges (0.1-200 ng mL-1) and low detection

16、limits (0.04 ng mL-1). The proposed method showed good precision, high sensitivity, acceptable stability and reproducibility, and could be used as a convenient and cost-effectively tool for hepatitis diagnosis at early stage.3. A new electrochemical immunoassay protocol for sensitive detection of-fe

17、toprotein (AFP, as a model) is designed using graphene sheet (CRG) to immobilize mediator toluidine blue (TB)-functionalized biomimetic interface as immunosensing probe and Fe3O4Au labeled horseradish peroxidase-anti-AFP conjugates (HRP-anti-AFP-Fe3O4Au) as trace label. The thionine functionalized g

18、raphene sheets used for the biosensor platform increased the surface area to capture a large amount of primary antibodies (Ab1), thus amplifying the detection response. Moreover, the low-toxic and high-conductive Fe3O4Au provided a high capacity nanoparticulate immobilization surface and a facile pa

19、thway for electron transfer. The immunosensor displayed a wide range of linear response (1-25 pg mL-1), low detection limit (0.31 pg mL-1), good reproducibility, selectivity and stability. The good performance of the immunosensor is attributed to the graphene sheets high surface-to-volume ratio whic

20、h allows the immobilization of a high-level of Ab1, Ab2, Thi and HRP and its good electrical conductivity which can improve the electron transfer among TB, HRP, H2O2 and electrode. The immunosensor was used to detect the AFP contents in serum samples from patients and satisfactory test results were

21、obtained in comparison with the ELIS A test results. Thus, graphene-based labels may provide many potential applications for the detection of different cancer biomarkers.4. A hydrogen peroxide sensor based on the glass carbon electrode modified with the thionine-graphene/gold nanoparticle nanocompos

22、ite (CRG-Thi/Au NPs/GCE) was fabricated. The applied potential was-0.3V, and the linearity range was from 0.002 to 0.7 mmol L-1 with a detetion limit of 0.64mol L-1, the experimental results demonstrate that the fabricated sensor was more sensitive for the H2O2 determination compared with CRG/GCE an

23、d CRG-Thi/GCE.【关键词】电化学传感器 甲苯胺蓝 硫堇 石墨烯 金纳米粒子 电催化 过氧化氢传感器【英文关键词】biosensors, nanocomposite graphene gold nanoparticle toluidine blue thionine electrocatalysis hydrogen peroxide sensor【目录】基于电活性纳米复合材料构建生物传感的研究摘要3-5ABSTRACT5-7第1章 绪论11-281.1 生物传感器11-151.1.1 生物传感器概况简介111.1.2 生物传感器的原理11-151.1.3 生物传感器的分类151.2

24、 免疫传感器简介15-181.2.1 免疫传感器的定义15-161.2.2 免疫传感器的工作原理161.2.3 免疫传感器的分类161.2.4 电化学免疫传感器16-181.3 酶传感器18-191.4 纳米材料在化学/生物分析及传感中的应用19-221.4.1 金纳米粒子在生物医学工程中的应用20-211.4.2 石墨烯在传感器中的应用21-221.5 总结与前景展望22-23参考文献23-28第2章 甲苯胺蓝-壳聚糖纳米复合物的制备及其在生物传感器构建中的应用28-422.1 引言28-292.2 实验部分29-312.2.1 试剂与仪器292.2.2 实验方法29-312.3 结果与讨论

25、31-382.3.1 CHIT-TB复合材料的红外光谱表征31-322.3.2 不同修饰膜的表面形貌表征32-332.3.3 电极修饰过程的电化学表征33-352.3.4 实验条件的优化35-362.3.5 免疫传感器的安培响应36-372.3.6 免疫传感器的重现性,稳定性和特异性372.3.7 样品测定37-382.4 结论38-39参考文献39-42第3章 甲苯胺蓝功能化石墨烯免疫传感器的构建及其甲胎蛋白检测应用42-523.1 引言42-433.2 实验43-443.2.1 试剂433.2.2 仪器43-443.2.3 石墨烯/甲苯胺蓝复合材料的制备(CRG-TB)443.2.4 制备免疫传感器443.3 结果与讨论44-493.3.1 石墨烯及其复合材料的电镜表征44-453.3.2 CRG-TB的光谱表征45-463.3.3 修饰电极的循环伏安特性463.3.4 修饰电