【作者】 张艳；

【导师】 黄承志；

【作者基本信息】 西南大学 ， 分析化学， 2012， 硕士

【摘要】 石墨烯自从2004年被发现以来,由于结构、机械、电学及化学特性在场效应晶体管、传感器、清洁能源设备和复合纳米材料等方面有着重要的应用。本文制备了氧化石墨烯,并在此基础上利用石墨烯作为共振能量转移受体,实现了对HIV病毒DNA的分析检测。同时,采用新的方法合成了还原型氧化石墨烯和荧光石墨烯,考察了其物理和化学性质,并进一步探讨了其作为共振能量转移供受体的性质。具体研究内容包括以下三个方面：(1)通过引入氧化石墨烯作为信噪比增强试剂,以人类免疫缺陷病毒1型(HIV-1)相关短DNA序列为例,开发了一种基于长程共振能量转移策略对DNA进行分析检测的简便方法。当体系中不存在靶物ssDNA时,探针ssDNA和Sybr GreenⅠ染料都会吸附到氧化石墨烯表面,此时由于染料和氧化石墨烯之间存在长程共振能量转移过程,所以Sybr GreenⅠ染料荧光被猝灭。当向体系中加入靶物ssDNA,此时靶物ssDNA和探针ssDNA会形成双链结构,由于DNA双链结构和氧化石墨烯较弱的π-π相互作用力,同时Sybr GreenⅠ染料嵌入DNA双链结构的凹槽,所以Sybr GreenⅠ染料的荧光得以恢复,据此高灵敏的检测DNA,检测限能达到0.31nM,并且能够检测碱基错配,该方法相对于其它检测特征DNA序列的方法,具有灵敏、简便、特异性高、抗干扰好的特点。(2)采用氧化石墨烯固体作为碳源,叶酸作为还原剂,制备了叶酸功能化还原型氧化石墨烯。值得注意的是,叶酸不仅作为还原剂,同时还可作为稳定剂,所制备的还原型氧化石墨烯在水溶液中能够稳定存在4个月以上,进一步从紫外吸收光谱、X射线衍射、红外光谱、拉曼光谱、透射电镜、热稳定性和细胞毒性等方面进行考察,所合成材料表现出较好的还原型氧化石墨烯性质,同时将所制备得到的材料用作共振能量转移受体,和氧化石墨烯进行对比,考察了对荧光素的淬灭,叶酸功能化还原型氧化石墨烯对染料的猝灭效果更好。(3)以表面活性剂PEG.600作为钝化试剂,开发了一种简单的水热法一步合成荧光石墨烯。由于表面活性剂PEG-600含有大量羟基官能团,所合成的荧光石墨烯能够在水溶液中稳定存在5个月以上,并且其具有较好的抗盐性和抗光漂白性,在pH为2.0-12.0的范围内,荧光强度稳定。更多还原

【Abstract】 As a result of special structure, mechanical, electronics and chemical properties, graphene have been importantly used in the fields of field effect transistors, sensors, clean energy devices and graphene-polymer nanocomposites since their discovery in 2004. In this paper, we prepared graphene oxide, and applied to analyse of HIV DNA detection in the foundation of using graphene oxide as the resonance energy transfer acceptor. At the same time, we prepared the graphene and photoluminescent graphene by the new methods, and investigated the physical and chemical properties of them, and then explored the properties of them as resonance energy transfer acceptor or donor. The main content is as follows:1. By introducing graphene oxide as signal-to-background ratio enhancer, a simple long range resonance energy transfer strategy for short DNA target with its sequence related to the human immunodeficiency virus type 1 is explored. In the absence of target ssDNA, both probe ssDNA and SG I dye are adsorbed on the surface of GO, and the fluorescence of SG I is quenched by GO following long range resonance energy transfer process. In the presence of target DNA, however, a double-stranded structure of DNA gets formed, and thus SG I dye can bind with double-standed DNA in the mode of intercalation and minor groove binding, keeping away from graphene oxide surface owing to the reduction of the interaction between the rings of the nucleotide bases and the honeycomb surface of GO. As a result, fluorescence emission from SG I dye gets enhanced with high signal-to-background. It was found that a detection limit of 0.31 nM could be achievable, and single-base-pair mismatches are easily detected. The strategy for sequence-specific DNA detection has sensitivity, simplicity, high specificity and anti-interference properties. 2. The preparation of folic-modified graphene was demonstrated using graphene oxide as carbon source and folic acid as reducing agent. It was noteworthy that folic acid is not only the reductant, but also stabilizer, and the folic-acid modified graphene can disperse in water for more than four months. Furthermore, ultraviolet-visible absorption spectroscopy, X-ray powder diffraction, fourier transform infrared spectrum, raman spectroscopy, transmission electron microscope pattern, thermal stability and cell toxicity was investigated, and the synthetic materials has good properties compared with other graphene. Simulanteously, compared with graphene oxide, the prepared folic-modified graphene quenched the fluorescein dye as resonance energy transfer acceptor is much better.3. A simple hydro thermal method was developed for preparation of photoluminescent graphene using surfactant PEG-600 as passivation reagent. Owning to a great quantity of hydroxyl group in the PEG-600 molecules, the prepared photolumineccent graphene can disperse in water for more than five months, and show good salt resistance and anti-photobleaching. The fluorescence intensity is stable during the pH 2.0-12.0.更多还原