【作者】 贾思思；

【导师】 樊春海；

【作者基本信息】 中国科学院研究生院（上海应用物理研究所） ， 无机化学， 2014， 博士

【摘要】 实现自下而上具有纳米级精确度的组装贵金属纳米颗粒是纳米技术的一个重要目标，有序组装的金属纳米颗粒阵列，基于其独特的表面等离子体共振性质，在纳米光子学（nanophotonics）及纳米电子学（nanoelectronics）方面都有重要应用。DNA纳米技术能够在纳米级精确度上控制纳米颗粒的定位，调控其相互作用，是有效控制纳米颗粒自组装的重要途径。 DNA折纸术，由200多条短链将一条长链M13固定成形状各异的二维、三维结构，其中每一条短链在DNA折纸结构上的位置是独一无二的，这使得DNA折纸结构具有纳米级可寻址性，是定位组装金属纳米颗粒的优秀模板。本文就主要利用DNA折纸术的结构多样性及纳米级可寻址性构建多种金属纳米图案，主要内容包括以下几点：1.首先我们由现在的简单二维DNA折纸通过粘性末端杂交构建各种形状的较大DNA折纸模板。为了能够利用一种简单的DNA origami tiles粘性末端杂交来得到高产率超级DNA折纸结构，为下一步组装金属纳米图案做准备，我们通过调节单个DNA折纸上伸出的粘性末端的个数，能有效提高形成三角DNA折纸结构六聚体的产率，利用同样的设计，我们合成了三角DNA折纸结构的二聚体、三聚体。同时，我们还构建了可光控调节的DNA折纸模板。偶氮苯存在顺反异构现象，具有光致异构性，其构形会随着光波长的变化改变其结构。当照射光波长小于400nm时，其结构为反向，可使修饰有偶氮苯的双链DNA接连，当用白光照射时，其结构为顺向，又可形成DNA双链结构。利用偶氮苯修饰的DNA做桥连DNA，我们实现对方块二聚体、多聚体形成与分散的光控调节。2.利用DNA折纸的纳米级可寻址性可精确定位金属纳米颗粒，我们利用这一点，通过DNA折纸上伸出的粘性末端与纳米金上修饰的DNA杂交将纳米级自组装到DNA折纸的特定位置，纳米金颗粒的几何构形及颗粒之间的间距由粘性末端位置确定。金属等离子体共振的强弱与其空间构形、纳米金颗粒大小，颗粒间间距大小都密切密切相关，而且对于小粒径纳米金来说，由于其散射截面太小，光学仪器采集单独一个纳米结构的光谱是十分困难的。我们以DNA折纸为模板构建小粒径纳米金颗粒开始，最后实现了组装30nm、50nm到80nm纳米金颗粒，构建大粒径纳米金颗粒的二聚体、三聚体及六聚体为下一章构建具有特殊光学效应的纳米金阵列打下基础。3.亚波长金属结构具有表面等离子共振性质，能与电磁场发生相互作用，这个性质使得亚波长金属结构能够在纳米金别操纵电磁场。我们利用DNA折纸为模板，构建了80nm纳米金二聚体、三聚体及四聚体，同时还组装了50nm-80nm纳米金各向异性二聚体。并且通过飞秒光刻在导电玻璃上打出标记物的方法实现了暗场显微镜与扫面电子显微镜共定位，原位采集纳米金团簇的暗场散射光谱，得到了类Fano共振（Fano-like resonance）现象。4.以上都是通过自组装金纳米颗粒的方法构建金属纳米图案，我们有通过在DNA折纸特定位点伸出DNA单链的方法在DNA折纸平面上引入缺陷，实现了在DNA折纸上纳米级分辨率无需种子的选择性铜金属化，在DNA折纸上成功构建了七点数字8数字88等铜金属图形，为构建纳米电路及纳米电学器件提供了可靠方法。更多还原

【Abstract】 The bottom-up organization of noble-metal nanoparticles (NPs) withnanometer-scale precision is an important goal in nanotechnology. Owing to theirunique surface-plasmon resonances,well-defind metal namoparticle arrys could beused to develop applications in nanophotonics and nanoelectronics. Enormousprogress has been made in the DNA guided organization of nanoparticles intodiscrete, one dimensional, two-dimensional and three-dimensional architectures.DNA nanotechnology is a vehicle for the controllable assembly of nanoparticles8because it enables the positioning of particles with nanoscale precision and thetailoring of their binding interactions. DNA origami, which is based on the folding along single-stranded DNA scaffold with the help of hundreds of short complementarystaple strands, can create almost any arbitrary2D even3D shapes.Every stable strandis unique on the DNA origami,which make it nano-addressable and a perfecttemplate for metal nanoparticles self-assembly.Here we constructed a variety of Metal nanopatterns using thenano-addressablity of DNA origami.1. First, we built a variety of shapes of superorigami using the simpletwo-dimensional DNA origami through the hybridization of the sticky ends. weadjusted the number of sticky ends projecting from the DNA origami, and getsuperorigami with high yield, which is prepared for the assembly of metalnanopatterns on DNA origami next step. We improved the yield of hexamer DNAorigami structures formed from the triangles effectively. Using the same design, wehave synthesized the triangular DNA origami dimer and trimer.2. The nano-addressablity of DNA origami made the self-assembly of metalnanoparticles (NPs) with nanometer-scale precision easily. We designed a strategy to organize gold nanopaticles that uses the hybirdization of sticky-ends projecting fromthe DNA origami with the DNA modified on gold nanoparticles. The positions of thepaticles and spacings between them were controlled by the positions of thesticky-ends. The plamonic coupling between the gold nanoparticles depend on thegeomitry of the nanostructures,the shap and size of the particles and the spacingbetween them. Especially with small particles, optical measurements on individualnanostructures become extremely difficult due to their smallscattering cross sections.We construted gold naoparticles clusters from the small one and got the5nm goldnaoparticle heptermaers on DNA origami with high yield.Then we extended to thebig gold nanoparticles whose diameters ranged from30nm to80nm. We constructeddimer,trimer and hexamer of these big gold nanoparticles.3. Sububwavelength metallic structures enable the broad manipulation ofelectromagnetic fields at the nanoscalebecause of their ability to support surfaceplasmons, which are oscillations of free electrons in metal that couple with theelectromagnetic field. We constructed80nm gold nanoparticle dimer, trimer,tetramer and50nm-80nm gold nanoparticle dimer. We realized the Dark-fieldmicroscopy and scanning electron microscopy colocalization theough the marker onthe conductive glass. With this method, we got the scattering spectru of these goldnanoparticle clusters and discover the Fano-like resonance on the asymmetric80nmgold nanoparticle tetramer.4. Herein we used a conceptually new, simple and straightforward in situmetallization method which utilizes artificial defects in DNA origami structure asnucleation and growth positions to achieve the large-scale site-specific copperplating with nano-resolution.We successfully constructed a variety of parttens, suchas "seven dots","digetal8"and "digital88", on the DNA origami through the selectivecpooer metallization.更多还原