DNA“索烃”介导的贵金属纳米粒子自组装体结构手性可控转换研究

The construction and functions of noble metal-based chiral nanostructures have attracted much attention in recent years due to their unique properties. However, how to realize the controlled and dynamic chirality conversion of the assemblies of metal nanoparticles remains as a challeng. On the basis of the previous research on DNA topoloigcal nanostructures, DNA nanomachines and the self assembly of metal nanoparticles, we will manage to tailor the chirality of metallic nanostructures and study the kinetics of the chirality conversion. In this proposal, DNA catenanes, constructed by multi-interlocked nucleic circles, will be used as the template to assemble DNA-modified gold or silver nanoparticles with different sizes, which will assoicate with the target circular units. The circles in the catenanes will be driven to perform mechanical motion, fueled by multi-environmental stimuli, to induce the change of topological structures of the catenane and the spatial positions of the metal nanoparticles, resulting in the reversible and continuous chiral conversion of the metallic self assemblies. We will also invesigate the effect of topology of DNA catenane and the combination of the nanoparticles on the handedness of the assembled metallic nanostructures, study the relationship between the chirality of the nucleic catenane and metal assemblies, as well as digging out the mechanism of chirality conversion of the assembled metal nanoparticles. In addition,logical nanoscale opticaldevices will be constructed, using the multifuels as inputs, the CD signals of the metallic assemblies as outputs and the feedback.

贵重金属手性纳米结构体的构建与功能研究近年来引起了人们的广泛关注，而如何实现金属纳米自组装结构手性的可控、动态转换仍是一项有挑战的课题。我们将立足于DNA拓扑结构、DNA纳米机器和金属纳米颗粒自组装的研究基础，探索贵重金属纳米结构体手性动态调控的有效方法。本项目将以多环互锁的DNA索烃为模板，将不同粒径的DNA修饰过的金、银纳米粒子组合组装至索烃目标单元；利用多重外界条件为驱动燃料，通过索烃组成单元方向可控的机械运动，变换索烃的拓扑结构和金属纳米粒子相对空间位置，实现金属纳米粒子自组装体结构手性的可逆、连续转换。考察DNA索烃的拓扑结构和金属纳米粒子组合方式对自组装体结构手性的影响，研究核酸结构手性和金属组装体圆二色的关系，揭示金属纳米粒子自组装体结构手性的转换机理。我们也将以外界驱动条件为输入指令、金属纳米粒子自组装体结构手性光学信号为输出及反馈输入指令，制备纳米光学逻辑器件。

贵金属纳米颗粒和纳米结构的手性光学现象近年来引起了人们的广泛关注，而如何实现光学活性行为的智能响应调控仍是一项有挑战的课题。本项目立足于DNA折纸纳米结构刚性、空间可寻址性和DNA构象的刺激响应性，以DNA纳米结构作为模板引导组装金纳米棒，通过对模板连接链的设计，构建了几何构型和光学活性可对多种环境变化响应的手性贵金属纳米结构；另一方面，设计了多种序列的DNA分子，将其吸附于具有葡萄糖氧化酶催化活力的金纳米颗粒表面形成手性配体选择层，通过控制环境变量，首次实现纳米颗粒对多种手性单糖底物的催化选择性的调控；进一步的，通过控制DNA配体和底物的手性，实现对纳米颗粒增长动力学的控制。该项目成果为贵金属纳米颗粒的光学活性和旋光选择性的控制和智能响应性研究提供了研究思路