摘要：本论文首先设计了单链DNA作为检测探针，基于葡萄糖加入后对目标DNA的切割从而引导的电流信号的改变实现了葡萄糖的高灵敏电化学检测。本论文分别设计了辅助探针和检测探针和并结合二茂铁修饰的发卡探针。首先将辅助探针在电极表面通过Au-S键固定，在检测探针存在下，与一种发卡探针杂交形成三明治结构，并相继打开二茂铁修饰的两种DNA的发卡结构，继而通过两种发卡探针交错性杂交而使杂交链式反应顺利发生，形成长链双螺旋DNA复合物模板，由于大量二茂铁在电极表面的固定而产生明显的氧化还原峰。同时，正电性的金纳米粒子可以通过静电吸附固定在双螺旋DNA模板使电流信号增强。然而，若首先将检测探针与葡萄糖、Fe2+和葡萄糖氧化酶预先孵育一段时间，检测探针将被切割成碎片，导致杂交链式反应不能在电极表面形成，由于二茂铁不能固定到电极的表面，电流信号将会下降。在最佳实验条件下，通过观察葡萄糖加入前后引起的二茂铁氧化还原峰电流信号的改变实现葡萄糖在浓度 60-3.0 nmol/L范围内的灵敏检测。同时该传感器在电化学葡萄糖检测中具有良好的选择性。51854

毕业论文关键词：正电性金纳米粒子  杂交链式反应  DNA模板 葡萄糖 电化学传感器

Hybridization chain reaction with gold nanoparticles used in detection of glucose

Abstract: A detection probe was designed for constructed the sensor firstly. Then, we  realized the highly sensitive glucose detection according to observe the electrochemical signal change before and after the addition of glucose, Fe2+ and glucose oxide. The sensor consists of assistant probe and detection probe coupled with Fc-modified DNA hairpins (H1 and H2). Firstly, the electrode surface was immobilized by using capture probe, and a sandwiched DNA complex could formed between the capture probe and DNA hairpin in the presence of the detection probe, and then resulted in the happen of hybridization chain reaction (HCR) for the formation of a nicked double-helix DNA complex. After that, numerous gold nanoparticles could adsorb onto such DNA strands based on electrostatic adsorption to amplify electrochemical signal. However, if the detection probe was incubated with glucose, Fe2+ and glucose oxide firstly, detection probe would be cleaved into DNA fragments, and then induced the happen of HCR, such result would directly induced the decrease of redox peak of Fc. Under optimal conditions, glucose could be detected in the concentration range from 60 to 3.0 nmol/L, and a detection limit of 22 pmol/L was obtained for glucose detection. Moreover, high selectivity could obtained for glucose detection

Keywords: Positively charged gold nanoparticles, hybridization chain reaction, DNA complex, glucose, electrochemical sensor

目录

前言 1

1.材料与方法 2

      1.1 供试材料 2

      1.2 实验试剂 2

      1.3 正电性金纳米粒子制备 2

      1.4 电化学方法检测葡萄糖 3

2. 结果与讨论 3

      2.1  金纳米粒子表征 3

      2.2 不同修饰电极的电化学表征 4

      2.3 实验条件的优化 5

      2.4 葡萄糖的定量测定 6

3讨论 6