DNA折纸术指导多级等离子体超结构的组装与性质研究

Chiral phenomena are widespread in nature, chiroptical plasmonic nanostructures exhibit optical response in the visible region have attracted more and more attention recently. However, it is still very challenging in the accurately assembly of anisotropic plasmonic nanomaterials into large scale and complex chiral plasmonic superstructures.. DNA nanotechnology based on the DNA's programmability could precisely control the sizes, spatial orientations and the functionalized surface of nanostructures, imparts surface-addressable capabilities to the gold nanorods, have been ideal templates to guide self-assembly of the plasma superstructures..In this proposal, the applicant propose to use the hexagonal barrel DNA origami as a template to encapsulate the surface-functionalized gold nanorods and reduce their own charge repulsion in the meantime, then the captured DNA out-extension strands chain on the DNA origami template would connect other wrapped gold nanorods specifically. The different hierarchical chiral plasmonic superstructures could be obtained by adjusting the number of gold nanorods and the spatial configuration. Lastly, their resultant plamonic chiroptical properties will be systematically investigated.

自然界中的手性现象广泛存在，近年来，具有在可见光波段手性光学响应特性的等离子体金属纳米结构吸引了越来越多的关注。然而将各向异性等离子纳米材料精确组装成大尺度、复杂的手性等离子超结构依然极具挑战；DNA纳米技术基于DNA分子的可编程性，能够将结构的尺寸、空间指向性以及表面功能化单元精确控制，将表面可寻址的能力赋予了金纳米棒，指导等离子体超结构的自组装。.本项目拟利用六边形桶状DNA折纸为模板，将表面功能化的金纳米棒封装其内同时降低自身电荷排斥，并在DNA模板外表面设计DNA捕获链进而特异性连接其他金纳米棒基元，得到多级等离子体超结构，通过调节金纳米棒的数目及空间构型等关键变量得到不同手性超结构，进一步研究组装体的手性光学性质，阐释其光学活性产生机制。

纳米尺度手性等离子基元的可控组装是当前纳米光子领域的热点和前沿研究方向。在本项目中，我们利用DNA折纸作为支架对各向异性的金纳米棒进行可控空间排布，结合DNA链置换反应赋予组装体动态响应能力。首先，我们基于DNA纳米技术构建了具有多达三个可区分的手性中心的等离子非对映异构体，并可选择性动态调整每一个手性中心以产生所需非对映异构体，产生特征性的手性光学信号。第二，我们提出了基于DNA折纸平台的DNA逻辑门计算策略，通过输入DNA分子信号，引起DNA折纸平台的构象改变并输出等离子手性信号，通过系统设计实现了一整套布尔运算逻辑门。项目研究成果将有助于理解和设计复杂的手性等离子纳米结构，并有希望在生物计算、生物传感和生物成像领域执行更多复杂任务。

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