DNA折纸结构用于形状可控纳米粒子的制备及其作为表面增强拉曼基底在中药检测中的应用

发布时间：2018-03-07 23:20

本文选题：DNA折纸　切入点：纳米粒子　出处：《广东药科大学》2017年硕士论文　论文类型：学位论文

【摘要】：DNA折纸结构的形状十分多样,几乎可以被构建成任意形状。但与其它材料的纳米粒子相比,DNA折纸结构的稳定性相对较差,在一定程度上限制了它的应用。如果能以DNA折纸结构为模板,制备出与其形状相同的其它材料的纳米粒子,则可将该纳米结构的尺寸和形状优势与材料的稳定性结合,以满足对不同形状不同材料纳米粒子的需求。近年来,非法对中药材进行人工染色的情况时有发生。在针对中药材中添加色素的检测方法中,拉曼光谱法因对样品无损伤,且对样品预处理的要求很低,甚至无需进行预处理,具有很大的优势。其中,表面增强拉曼散射(Surface-Enhanced Raman Scattering,SERS)光谱技术因具有很高的检测灵敏度而被广泛应用。而表面增强拉曼散射的增强效应与其活性基底的形状有关。因此,寻找形状多变、可控性强的纳米粒子来做SERS基底十分必要。若将DNA折纸结构与SERS基底结合起来,可极大促进表面增强拉曼光谱的发展。基于以上背景,本文首先对DNA折纸结构在不同条件下的稳定性进行了研究,为其在不同领域的应用提供理论基础。实验结果表明,DNA折纸结构在缓冲液中很稳定,可长期保存,但受温度的影响较大,只能在低于解离温度的环境中存在;当把DNA折纸结构固定在基底上并置于空气中时,其稳定性很差,不能长期保存,但此时其对温度的耐受程度比较强,可耐受约200℃的高温;另外,溶液中的镁离子浓度对DNA折纸结构的稳定性起着关键作用,且在一定范围内,随着镁离子浓度的增高,DNA折纸结构逐渐出现团聚趋势。其次,在DNA折纸结构稳定存在的前提下,本文发展出了一种以其为模板制作二氧化硅纳米粒子的方法,通过一种助结构导向剂的连接,在DNA折纸结构的表面包裹一层二氧化硅,合成与其结构形状相同的二氧化硅纳米粒子。通过该种方法可制备出形状可控的纳米粒子。本文采用上述方法合成了矩形、滚筒型、五角星形和四面体线框结构的二氧化硅纳米粒子,并通过原子力显微镜(AFM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱(EDS)、X射线衍射仪(XRD)、小角X射线散射仪(SAXS)等方法对粒子的性质进行分析。结果表明,使用该方法所得粒子为核壳结构,且壳层二氧化硅为无定型的介孔结构。在不同形状的二氧化硅纳米粒子外喷一层金,可将其作为SERS基底,对中药中的柠檬黄和日落黄进行拉曼检测。实验结果表明,滚筒型的粒子的SERS效应最强,可以其为SERS基底可对中药中的非法添加色素进行拉曼检测。
[Abstract]:The DNA origami structure shape is very diverse, almost can be constructed into any shape. But the nanoparticles and other materials compared to the stability of DNA origami structure is relatively poor, which limits its application to some extent. If the DNA origami structure as template, the preparation of nanoparticles with the shape of other materials of the same, then can be combined with the stability of the nano structure size and shape and material advantages, to meet the different needs of different shape material nanoparticles. In recent years, the illegal artificial coloring of the Chinese herbal medicines have occurred. The detection method for adding pigment in Chinese herbal medicine, Raman spectroscopy method without damage to the sample, and the sample pretreatment is very low, even without pretreatment, has great advantages. The surface enhanced Raman scattering (Surface-Enhanced Raman, Scattering, SERS) spectroscopy technology Because the operation has high detection sensitivity and is widely used. While the surface enhancement effect and active substrate shape of Raman scattering. Therefore, looking for the shape changing, nanoparticles controllability to SERS substrate is necessary. If the DNA origami structure and SERS substrate together, which can greatly promote the development of surface enhanced Raman spectroscopy. Based on the above background, this paper studies the stability of DNA origami structure under different conditions, and provide a theoretical basis for its application in different fields. The experimental results show that the DNA origami structure is very stable in buffer, can be stored for a long time, but is affected by temperature, can only exist in the below the dissociation temperature; when the DNA origami structure fixed to the substrate and placed in the air, its stability is very poor, can not be stored for a long time, but this time the tolerance temperature is relatively strong, Can withstand high temperature of about 200 DEG C; in addition, the magnesium ion concentration in solution plays a key role on the stability of DNA origami structure, and in a certain range, with the increase of the concentration of magnesium ions, DNA origami structure gradually appeared agglomeration trend. Secondly, on the premise of the existence of DNA origami stable structure, this paper developed a method of making the template for the silica nanoparticles, connected by a co structure directing agent, on the surface of DNA origami structure covered with a layer of silica, silica nanoparticles synthesis and structure of the same shape. Through this kind of method can be prepared. The rectangular shape controlled nanoparticles synthesized by this method. Drum type, Pentagram and tetrahedron frame structure of silica nanoparticles, and by atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy spectrum ( EDS), X ray diffraction (XRD), small angle X ray scattering (SAXS) properties and other methods of particle were analyzed. The results show that the method for using the particle obtained core-shell structure, and the shell of silica mesoporous structure of amorphous silica nano particles. In spraying a layer of different shapes gold, which can be used as SERS substrates, Raman detection of traditional Chinese medicine in lemon yellow and sunset yellow. The experimental results show that the strongest effect of SERS roller type particles, can the SERS base of Chinese herbal medicine illegally added pigment for Raman detection.

【学位授予单位】：广东药科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.37;R284

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