基于DNA折纸组装金纳米粒子及其手性性质研究

发布时间：2018-06-20 01:43

本文选题：DNA折纸术 + 金纳米棒　；参考：《华东师范大学》2015年硕士论文

【摘要】：手性纳米晶体和纳米结构在最近几十年引起了相当大的关注。但是,利用人工合方法合成的手性纳米材料,仍然存在巨大的挑战。目前,自组装是一种高效的制备手性纳米材料的方法,可以用来制得具有不同几何构型的手性超结构。对于纳米结构的手性研究表明,空间构型,纳米基元的间距和位置等都是影响手性信号的重要因素。最新兴起的结构DNA纳米技术,为我们自下而上的构建复杂的纳米结构组装体提供了可能。DNA分子中特定碱基之间相互配对形成双螺旋结构,是一种极佳的具有特异性识别功能的构建纳米结构的材料。其中最典型的即是DNA折纸技术(DNA Origami),由于其具有绝佳的可寻址性,因此,我们利用DNA折纸为模板,可以在纳米尺度精确地可选址的固定组装金属纳米粒子。本文以DNA折纸为模板,先后组装了金纳米棒和金纳米棒-金纳米球二聚体,并对其结构、手性性质进行研究,研究内容和主要结论如下：1、通过在DNA折纸上不同位置的设计捕获链,成功精确地组装了金纳米棒和金纳米棒-金纳米球二聚体的手性结构,在可见光区域测量到了稳定的手性信号。2、通过研究了精确组装在DNA折纸模板上的金纳米棒(AuNR)或者金纳米球(AuNS)的组装体的光学响应信号,发现等离子体的圆二色性(Circular Dichroism, CD)是高度取决于于DNA折纸模板上的二聚体相对于DNA轴的方向和纳米颗粒之间的距离。DNA模板起到了主要的作用,它不仅可以调控组装任意的具有手性空间构型的结构,而且诱导等离子体结构产生手性。3、DNA折纸结构本身由于DNA分子的有序排列使其分子偶极与金纳米棒表面等离子产生共振,从而诱导对称性的金纳米棒结构在其等离子共振谱区产生圆二色谱信号。当纳米粒子之间的间距相当时,金纳米棒或者金纳米球二聚体中的两个粒子位于DNA折纸模板同侧和异侧时的光学信号强度具有显著差异。偶极距离(Dipole-dipole distances)在等离子体手性产生过程中起着至关重要的作用,并且实验结果与建立模型进行计算的结果高度吻合。从实验和理论上都揭示了DNA这一手性分子诱导产生手性的根本原因。
[Abstract]:Chiral nanocrystals and nanostructures have attracted considerable attention in recent decades. However, there are still great challenges in the synthesis of chiral nanomaterials by artificial synthesis. At present, self-assembly is an efficient method for preparing chiral nanomaterials, which can be used to prepare chiral superstructures with different geometric configurations. The chirality of nanostructures shows that the spatial configuration, the spacing and location of the nanostructures are the important factors affecting chiral signals. The latest rise in structural DNA nanotechnology provides the possibility for us to build complex nanostructural assemblies from the bottom up, pairing specific bases in DNA molecules to form double helix structures. It is an excellent material for the construction of nanostructures with specific recognition function. DNA origami technology is the most typical one. Because of its excellent addressable ability, we use DNA origami as a template to fix and assemble metal nanoparticles at nanometer scale. In this paper, gold nanorods and gold nanorods were assembled by DNA origami as template, and their structures and chiral properties were studied. The contents and main conclusions are as follows: 1. The chiral structures of gold nanorods and gold nanospheres dimer were successfully assembled by designing different positions of capture chains on DNA origami. The stable chiral signal. 2 was measured in the visible region. The optical response signals of the gold nanorods or gold nanospheres AuNSs assembled on the DNA origami template were studied. It is found that the circular dichroism of plasma (CDCD) is highly dependent on the direction of the dimer on the DNA origami template relative to the direction of the DNA axis and the distance between the nanoparticles. The DNA template plays a major role. It can not only regulate and assemble any chiral spatial structure, but also induce the structure of plasma to produce chiral .3DNA origami structure itself, which is caused by the ordered arrangement of DNA molecules and the plasmon resonance between the molecular dipole and the surface of gold nanorods. Thus the symmetrical gold nanorods are induced to produce circular dichroism signals in the plasma resonance region. When the distance between nanoparticles is equal, the optical signal intensity of two particles in gold nanorods or gold nanospheres dimer is significantly different when they are located on the same side of DNA origami template and on the other side. Dipole-dipole distancesplays an important role in the generation of plasma chirality, and the experimental results are in good agreement with those calculated by the model. Both experimental and theoretical results show that DNA is a chiral molecule that induces chirality.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O614.123;TB383.1

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