基于双信号策略的电化学核酸适体传感器研究

发布时间：2018-02-28 21:22

本文关键词： 电化学传感核酸适体双信号疾病标志物溶菌酶　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：疾病标志物通常是指一类具有特异性的生化指示剂,其可以作为疾病诊断、疾病监测以及药物筛选等的重要依据。然而大多数的疾病标志物在人体中含量极低,因此很难对实际样品中疾病标志物准确检测,这种情况极大地制约了疾病标志物检测在临床实践中的应用。电化学核酸适体传感器(E-AB)因具有了高的灵敏度、强的特异性、快的响应速度、易于微型化和集成化等特点被广泛应用于分析检验中。本文以检测实际样品中超低浓度疾病标志物为目的,通过设计不同的双信号策略建立了两种双信号E-AB以实现对溶菌酶的便捷、快速、精准检测。这对于一些重大疾病的病前预防、早期诊断及治疗监测等方面具有十分重要的意义。本研究设计了一种结合“signal-on/signal-off"和“labeling/label-free”的策略构建的E-AB用于对溶菌酶的高灵敏与选择性检测。首先,将二茂铁修饰在单链DNA上作为一个电化学信号标记物以提供“signal-on”的信号;其次,带正电的六氨合钌离子通过静电作用吸附在带负电荷的DNA磷酸骨架上作为另一个电化学信号标记物以提供免标记的“signal-off'的信号。与单信号相比较,双信号的叠加(|AIRuHex| +△IFc)提高了该传感器对溶菌酶检测的灵敏度,检测限达到0.8 pM。基于将金属纳米颗粒的比色检测方法“嫁接”到电化学检测平台上的策略,本研究设计了一种可以用于检测溶菌酶的传感方法。为了实现该“嫁接”过程,我们首先制备了一种基于目标物引发下DNA-金纳米颗粒传感单元聚集的比色核酸适体传感器,之后将该检测原理“嫁接”到电化学平台上制备出操作简便、灵敏度高和稳定性好的E-AB。与比色核酸适体传感器(线性范围:5nM-500nM;检测限:0.9nM)相比,制得的E-AB线性范围更宽(1pM-10nM),检测限更低,可达到0.3 pM。
[Abstract]:Disease markers usually refer to a class of specific biochemical indicators, which can be used as an important basis for disease diagnosis, disease surveillance and drug screening. However, most disease markers are extremely low in the human body. Therefore, it is difficult to detect disease markers accurately in real samples, which greatly restricts the application of disease markers in clinical practice. Electrochemical aptamer sensor E-ABM has high sensitivity and specificity. The characteristics of rapid response, easy miniaturization and integration are widely used in the analysis and testing. The purpose of this paper is to detect ultralow concentration disease markers in actual samples. By designing different dual signal strategies, two kinds of double signal E-AB are established to realize the convenient, rapid and accurate detection of lysozyme. Early diagnosis and treatment monitoring are of great significance. In this study, an E-AB strategy combined with "signal-on/signal-off" and "labeling/label-free" was designed to detect lysozyme with high sensitivity and selectivity. Ferrocene was modified on single-stranded DNA as an electrochemical signal marker to provide "signal-on" signal. The positively charged ruthenium hexaamine ion is adsorbed on the negatively charged DNA phosphoric acid skeleton by electrostatic interaction as another electrochemical signal marker to provide a signal-free "signal-off" signal, compared with a single signal. Double signal superposition (AIRuHex IFC) improves the sensitivity of the sensor to lysozyme detection, reaching a detection limit of 0.8 pM.Based on the strategy of "grafting" the metal nanoparticles colorimetric detection method to the electrochemical detection platform, In this study, we designed a sensing method for detecting lysozyme. In order to realize the grafting process, we first prepared a colorimetric nucleic acid aptamer sensor based on DNA-gold nanocrystalline sensor unit. The detection principle was then "grafted" onto the electrochemical platform to prepare E-ABs with simple operation, high sensitivity and good stability. Compared with colorimetric nucleic acid aptamer sensors (linear range: 5nM-500nM; detection limit: 0.9nMM), The linear range of E-AB is wider than that of 1pM-10nMN, and the detection limit is lower, reaching 0.3 pM.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R446;O657.1;TP212

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