基于激子—等离子体激元共振能量转移的有机光电化学晶体管生物传感器

发布时间：2018-01-09 04:22

本文关键词：基于激子—等离子体激元共振能量转移的有机光电化学晶体管生物传感器　出处：《深圳大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,有机电化学晶体管(OECT)已被广泛应用于生物传感领域,其具有成本低、容易制备、工作电压低(1 V)、生物兼容性好、易微型化、可制成柔性器件等诸多优点。由于OECT结合了传统电化学检测的优点,并且同时具有传感和信号放大的功能,在生物分子检测中具有非常高的灵敏度。另一方面,光电化学(PEC)生物传感技术在分析化学领域正受到越来越广泛的关注。PEC生物传感是在传统电化学检测技术基础上发展出来的一种生物传感技术,由于结合了光激发信号与电检测信号两个技术,很大程度的消除了背景信号,使得PEC生物传感检测的灵敏度很高。由于这两种传感技术优势互补,且从工作原理上有合适的结合点,因此本论文将PEC体系中的工作电极作为OECT体系中的栅电极,构建一种基于有机光电化学晶体管(OPECT)的新型、具有更高灵敏度的生物传感技术,并将其应用于DNA传感和免疫传感(检测沙门氏菌)中,实现对生物分子的高灵敏、高特异性检测。主要围绕材料与器件的制备、新型传感技术的构建、OPECT在DNA传感中的应用、OPECT在免疫(沙门氏菌)传感器中的应用等四个方面展开探讨。研究了硫化镉量子点(CdS QDs)和金纳米颗粒(Au NPs)的制备,并利用透射电子显微镜、紫外可见光谱仪和荧光光谱仪等对其性能进行表征。结果表明,两者的尺寸都约为5±1 nm,粒径大小均匀,分散性良好。CdS QDs有较宽的紫外吸收峰,适合作为PEC及OPECT生物传感器的基底材料,并且CdS QDs的荧光发射峰与Au NPs的紫外吸收峰有很大的重叠,有利于激发Au NPs的表面等离子体共振(SPR),进而在两种粒子间迅速产生激子-等离子体激元相互作用(EPI)。成功制备了OPECT器件,并对其电学性能进行了表征。结果表明,所制备的OPECT器件在0.1 M AA(100 mM PBS配制)溶液中能够稳定工作,并且在0~0.6 V的V_(GS)范围内,沟道电流的可调范围大于一个数量级,有利于开发高灵敏的生物传感器。构建了基于OPECT的新型传感技术并对其工作原理进行探讨。包括测试平台的搭建、配套的电解池结构设计以及对相关的测试参数进行优化,最终搭建的实验平台能够同时满足OPECT及PEC的电信号检测要求。通过对OPECT新型传感技术工作原理的探索我们发现,当在合适的光激发下,栅电极上的光电活性半导体材料发生电子跃迁并伴随电荷转移,产生的光电压导致栅电极/电解质界面电势发生变化,从而引起器件的有效栅电压发生变化,最终通过器件沟道电流的变化反映出来。研究了OPECT在DNA传感中的应用。结果表明,基于位阻效应的有机光电化学晶体管DNA传感器对10个碱基的无标记目标DNA的检测极限为10 nM,其原理主要是基于目标DNA对栅电极表面电荷转移的阻碍作用。利用Au NPs对目标DNA进行标记后,传感器的检测极限最低可达1 fM,比基于位阻效应的DNA传感器的检测极限降低了7个数量级,这主要归功于CdS QDs与Au NPs之间的EPI效应使得栅电极表面的电荷转移大幅度减弱。此外,通过研究粒子间距对EPI效应的影响发现,在EPI效应检测体系中位阻效应和EPI效应两者同时都有贡献。同时,在相同传感体系下,我们发现OPECT体系的检测极限比传统PEC体系低1~2个数量级,说明OPECT具有更高的检测灵敏度。研究了OPECT在免疫(沙门氏菌)传感中的应用。结果表明,基于位阻效应的OPECT沙门氏菌传感器对沙门氏菌的检测极限为102 cells/mL,其传感原理主要是基于沙门氏菌对栅电极表面电荷转移的阻碍作用。此外,通过Au NPs标记沙门氏菌,引入CdS QDs与Au NPs间的EPI效应,沙门氏菌传感器的检测极限可达10 cells/m L,相对于单纯基于位阻效应的沙门氏菌传感器检测结果降低了一个数量级。我们相信,该传感技术具有非常高的普适性,可拓展到病毒、海洋微生物、细胞检测等诸多领域的研究,具有较好的可持续科学研究价值。
[Abstract]:In recent years, organic electrochemical transistors (OECT) have been widely used in the field of biosensors, which has the advantages of low cost, easy preparation, low working voltage (1 V), good biocompatibility, easy miniaturization, can be made of flexible devices and many other advantages. The advantages of OECT combined with conventional electrochemical detection, and at the same time with sensing and signal amplification function, has very high sensitivity in the detection of biological molecules. On the other hand, photoelectrochemical (PEC).PEC biosensor biosensor technology in the field of analytical chemistry is more and more widely is a biological sensing technology developed based on traditional electrochemical detection technology, due to the light the excitation signal and electric signal detection technology combined with the two, largely eliminate the background signal, the sensitivity of PEC biosensor detection is very high. Because of these two kinds of complementary sensing technology advantage, and from work The principle has the right combination of points, so the working electrode in the PEC system as a gate electrode in the OECT system, the construction of an organic photoelectric transistor (OPECT) based on the model, biological sensing technology has high sensitivity, and applied to the DNA sensor and the immune sensor (detection of Salmonella in the implementation of biological molecules) with high sensitivity and high specificity. The detection mainly focus on materials and devices for the preparation of the construction of new sensing technology, the application of OPECT in the DNA sensor, OPECT in immune (Salmonella) to discuss the four aspects of the sensor's application. The study of cadmium sulfide quantum dots (CdS QDs) and gold nanoparticles (Au NPs) were prepared using transmission electron microscopy, characterized the UV Vis spectroscopy and fluorescence spectroscopy. The results show that both the size of about 5 + 1 nm, uniform particle size, dispersion Good.CdS QDs has a broad UV absorption peak, suitable as a base material PEC and OPECT biosensors, UV and fluorescence emission peak of CdS QDs and Au NPs absorption peaks have great overlap, is conducive to the surface plasmon resonance excitation of Au NPs (SPR), and then rapidly produce exciton plasmon in the two kinds of interaction between particles (EPI). The OPECT device was successfully prepared, and the electrical properties were studied. The results showed that the prepared OPECT device at 0.1 M AA (100 mM PBS preparation) solution can work steadily, and in the 0~0.6 V V_ (GS) range. The channel current adjustable range is more than an order of magnitude, is conducive to the development of high sensitive biosensor. The construction of new sensing technology of OPECT and its working principle were discussed. Based on including testing platform, supporting structure design and the electrolysis cell to the associated test The experimental parameters were optimized, and ultimately build the platform can satisfy the requirements of the signal detection of OPECT and PEC. Through the exploration of the new OPECT sensor technology working principle we found that when appropriate excitation light, photoelectric active semiconductor material gate electrode on the electronic transition occurs with charge transfer caused by gate photovoltage the electrode / electrolyte interface potential changes, changes in effective gate voltage causing device, finally by changing the channel current of the device reflected. On the application of OPECT in the DNA sensor. The results show that the organic chemical sensor photoelectric transistor DNA steric effect of 10 nucleotides unlabeled target DNA detection limit based on the 10 nM, the main principle is to hinder the target DNA on the gate electrode surface based on charge transfer. To mark the target DNA by using Au NPs, sensor The lowest detection limit was 1 fM, the detection limit of DNA sensor based on the steric effect is reduced by 7 orders of magnitude, which is mainly attributed to the EPI effect between CdS QDs and Au NPs makes the charge transfer gate electrode surface is greatly reduced. In addition, the EPI should be found to affect the effect through the study of particle spacing, in EPI effect testing system of steric effect and EPI effect both contribute. At the same time, in the same sensing system, we found that the OPECT system than the traditional PEC system with low detection limit of 1~2 orders of magnitude, indicating that OPECT has a higher detection sensitivity. The research of OPECT in immune (Salmonella) sensing application the detection limit of OPECT. The results showed that Salmonella sensor steric effect of Salmonella based on 102 cells/mL, the sensing principle is the main obstacle of Salmonella transfer on the gate electrode based on surface charge. In addition, Through the Au NPs marker of Salmonella, the introduction of EPI CdS QDs and Au NPs effect, the detection limit can reach Salmonella sensor 10 cells/m L, compared with the pure Salmonella sensor steric effect detection result is reduced by one order of magnitude based. We believe that this technology has very high universality. That can be extended to the virus, marine microorganisms, cell detection and many other fields, with the value of sustainable scientific research better.

【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212.3

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