基于新型碳材料构建高性能光电化学适配体传感器用于抗生素检测研究
发布时间:2018-05-03 08:16
本文选题:石墨相C_3N_4 + 氧化石墨烯 ; 参考:《华中科技大学》2016年博士论文
【摘要】:光电化学传感是基于光电转换而发展起来的一种新型分析方法,因具有装置简单、价格便宜及灵敏度高等优势,而被广泛用于各种物质的分析检测。光电化学核酸适配体传感器是以适配体为特异性识别元素所构建的具有高选择性的光电化学传感器,其中光电活性材料是传感器核心组成部件,其光电转换效率对传感器的响应性能有很大的影响,因此,开发具有高光电转换效率的光电活性材料是发展此类高性能传感器的有效途径之一。另一方面,抗生素滥用问题日益严峻:抗生素滥用不仅导致其对水体及土壤产生严重的危害,例如破坏生态系统及产生“超级细菌”;而且,其对人体也产生各种危害,如使人体产生耐药性、损害人体器官和产生各种过敏反应或变态反应等。因此,发展快速、准确的抗生素残留物检测方法具有重要的意义。本论文在开发几种具有高光电活性碳材料基础上,结合核酸适配体,发展了多种高性能的光电化学核酸适配体传感器,用于抗生素的高灵敏度、高选择性检测,主要研究内容如下:(1)研制在水中有良好分散性的石墨相氮化碳(w-g-C3N4)和氧化石墨烯(GO)的复合材料作为可见光光电活性材料,以与卡拉霉素具有特异性作用的适配体为识别元件,构建了一种用于检测卡拉霉素的新型光电化学适配体传感器。研究结果发现,适量的GO掺杂能有效地提升w-g-C3N4的可见光光电流响应,有利于构建高灵敏光电化学传感器;而且,GO/w-g-C3N4拥有大的比表面积和π-共轭结构,可与适配体通过π-π堆砌作用与其结合固定在传感器表面,为适配体的固定提供了优异的平台;当待测液中有卡拉霉素时,传感器上的适配体可捕获卡拉霉素分子,使光电流得到提升,在优化条件下,传感器的光响应电流与卡拉霉素浓度在1nM~230nM范围为存在线性关系,检测限为0.2 nM;此外,该传感器具有很高的选择性、良好的重现性和稳定性。这些研究结果表明,GO/w-g-C3N4复合材料与适配体组合可成功地用于构建高性能光电化学适配体传感器。(2)用一步水热法制备氮掺杂石墨烯量子点(N-GQDs)作为传感器的核心光电转换材料,利用无标记的核酸适配体作为生物识别元件,构建用于检测氯霉素的光电化学适配体传感器。透射电镜表征显示,所制备的N-GQDs以2.14 nm平均粒径窄尺寸分布;X射线光电子能谱仪和红外光谱分析表明氮原子已成功地掺杂进了GQDs;紫外-可见吸收光谱测试结果表明,氮掺杂能显著提升GQDs在可见光区的吸收,从而有效地提升了GQDs的光电活性;另一方面,N-GQDs的π-共轭结构可通过π-π堆砌作用与适配体固定结合。基于这种适配体与N-GQDs构建的传感器对不同浓度的氯霉素有良好的光电响应性能,线性响应范围为10 nM~250 nM,检测限为3.1 nM。而且,传感器具有高灵敏度、高选择性的特点,已成功地应用于实际样品中氯霉素的检测。(3)制备了g-C3N4与CdS量子点(CdS QDs)的复合光电材料,用于构建四环素检测的光电化学适配体传感器。对于所研制的g-C3N4-CdS QDs复合材料,表面形貌观察表明,平均尺寸约4 nm的CdS QDs以紧密接触方式分布在g-C3N4表面上;紫外-可见漫反射光谱显示,g-C3N4在可见光区的吸收因CdS QDs的耦合而显著增强;与单组分光电材料相比,g-C3N4-CdS QDs复合材料具有较高的光电化学活性。将此g-C3N4-CdS QDs复合材料用作传感器组件,并在其上固定适配体作生物识别元件,构建了一种用于四环素检测的可见光驱动的光电化学适配体传感器,对四环素的线性响应范围为10 nM-250 nM,检测限为5.3 nM。本研究成功地证实,经CdS QDs敏化后的g-C3N4可用于发展高灵敏度、高选择性的光电化学传感器、是一种极具应用前景的可见光电活性复合纳米材料。
[Abstract]:Photoelectrochemical sensing is a new analytical method developed based on photoelectric conversion. It is widely used for analysis and detection of various substances because of its simple device, cheap price and high sensitivity. Photoelectrochemical nucleic acid aptamer sensor is a highly selective light based on aptamer as a specific identification element. The photoelectric active material is the core component of the sensor, and the photoelectric conversion efficiency has a great influence on the response performance of the sensor. Therefore, it is one of the effective paths to develop the high performance photoelectric active material with high photoelectric conversion efficiency. On the other hand, the problem of antibiotic abuse is becoming more and more important. Severe: the abuse of antibiotics not only causes serious harm to water and soil, such as destroying the ecosystem and producing "superbacteria", but also produces various hazards to the human body, such as the resistance to the human body, the damage of human organs and the production of various allergic reactions or allergies. On the basis of developing several high optoelectronic active carbon materials and combining with nucleic acid aptamers, a variety of high-performance photochemical nucleic acid aptamers are developed in this paper, which are used for high sensitivity and high selective detection of antibiotics. The main contents are as follows: (1) development in water A well dispersed graphite phase carbon nitride (w-g-C3N4) and graphene oxide (GO) composite was used as a visible light photoactive material, and a novel photophotochemical aptamer sensor used for the detection of Cara mycin was constructed with a specific ligand with Cara mycin. The results showed that a proper amount of GO was doped. It is beneficial to improve the visible light current response of w-g-C3N4, which is beneficial to the construction of highly sensitive photochemical sensors. Moreover, GO/w-g-C3N4 has a large specific surface area and a PI conjugated structure, which can be combined with the aptamers by pion pion stacking and immobilized on the surface of the sensor, and provides an excellent platform for the fixation of the adapter. In the case of Cara mycin, the aptamers on the sensor can capture the Cara mycin molecule and improve the photocurrent. Under optimal conditions, the optical response current of the sensor is linear with the range of 1nM to 230nM in the range of 1nM to 230nM, and the detection limit is 0.2 nM; in addition, the sensor has high selectivity, good reproducibility and stability. The results show that the combination of GO/w-g-C3N4 composites and aptamers can be successfully used in the construction of high performance photochemical aptamers. (2) the preparation of nitrogen doped graphene quantum dots (N-GQDs) by one step hydrothermal method as the core photoelectric conversion material of the sensor, and the use of unlabeled aptamers as a biometric element. The photoelectrochemical aptamer sensor used for the detection of chloramphenicol was constructed. The transmission electron microscope showed that the prepared N-GQDs was distributed in a narrow size of 2.14 nm, and the X ray photoelectron spectroscopy and infrared spectroscopy showed that the nitrogen atoms had been successfully doped into the GQDs; the UV visible absorption spectra showed that the nitrogen doping could be significant. The absorption of GQDs in the visible region is enhanced and the photoactivity of GQDs is effectively enhanced; on the other hand, the PI conjugated structure of N-GQDs can be immobilized with the aptamer by the pion pion stack. The sensor based on this aptamer and N-GQDs has good photoelectric response to chloramphenicol of different concentrations, and the linear response range is 10. NM ~ 250 nM, with a detection limit of 3.1 nM. and the sensor has high sensitivity and high selectivity, has been successfully applied to the detection of chloramphenicol in actual samples. (3) a composite photoelectric material of g-C3N4 and CdS quantum dots (CdS QDs) is prepared for the construction of a photochemical aptamer sensor for tetracycline detection. For the developed g-C3N4-CdS QD The surface morphology of s composites shows that the CdS QDs with an average size of about 4 nm is distributed on the g-C3N4 surface in close contact, and the UV visible diffuse reflectance spectra show that the absorption of g-C3N4 in the visible region is significantly enhanced by the coupling of CdS QDs. Compared with the single component optoelectronic materials, the g-C3N4-CdS QDs composite has a higher photoelectrochemistry. Using this g-C3N4-CdS QDs composite as a sensor component and immobilized the aptamer as a biometric element, a photochemical aptamer sensor driven by visible light for tetracycline detection is constructed. The linear response range to tetracycline is 10 nM-250 nM, and the detection limit of 5.3 nM. is successfully confirmed by Cd. The g-C3N4 sensitized by S QDs can be used for the development of high sensitivity, high selectivity photochemical sensors. It is a promising visible photoactive composite nanomaterial.
【学位授予单位】:华中科技大学
【学位级别】:博士
【学位授予年份】:2016
【分类号】:O657.1;TP212.2
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本文编号:1837722
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