石墨烯-金纳米自组装结构光学活性机制及增强调控

Thanks to the synergistic effect of nanoscale building blocks and structure configurations, nanoparticle assemblies usually display intensive optical activities. This project will perform controllable nanomaterials synthesis, nanoparticle interface functionalization and stabilization, and DNA hybridization based programmable assembly technology to construct high yield and optical properties enhanced graphene-gold self-assembled nanostructures, and investigate the dynamic self-assembly process. The project will focus on the relation between the electronic structure, Plasmon coupling and electromagnetic coupling, electromagnetic enhancement and optical activity enhancement with regarding to electronic circular dichroism, vibrational circular dichroism, optical rotatory dispersion and Raman optical activity as well as surface enhanced Raman scattering and their relations to demonstrate the mechanism of optical activity enhancement, and establish theoretical models. Finally, based on optical activity enhanced nanostructures, the interaction between graphene-gold self-assembled nanostructures and biomolecules induced disassembly process will be studied to develop multi-signals based biomolecules monitoring system. This project will target to gain significant progresses in methodology of chiral superstructure assemblies, electronic structure and assembly configuration-activity relationship as well as properties regulations, and obtain original scientific research achievements. This project will provide powerful scientific proof and basic support for the fabrication of optical enhanced materials, and the construction of the multi-signals theoretical system.

纳米粒子自组装表现出与组装基元和结构构型相关联的光学性质，纳米粒子协同效应产生强的光学活性。本项目拟通过纳米材料可控合成、纳米界面功能化和稳定化修饰，DNA程序化杂交组装技术，构建高产率、光学增强的石墨烯-金纳米自组装结构，进行自组装动态过程研究。重点研究手性自组装中电子结构、等离子耦合及电磁耦合，电磁场增强和光学活性增强相关的电子圆二色谱、振动圆二色谱、旋光光谱和拉曼旋光光谱及表面增强拉曼及其关联规律，阐释光学活性增强机制，建立理论模型。最后，基于光学活性增强自组装结构，研究石墨烯-金纳米结构与生物分子解组装规律，发展多信号监控生物分子方法体系。通过项目实施，期望在手性纳米超结构组装方法学、电子结构、组装体构型与性质的构效关系及性质调控等方面取得重要进展，获得原创性科研成果。项目研究为光学增强纳米材料的构筑、多信号调控理论体系的建立提供有力的科学依据和基础支持。

手性纳米材料在催化、生物传感以及光学显示等各个领域都显示出了比较大的潜力。研究纳米结构的光学活性机制及增强效应，对于生物传感分析与成像具有重要意义。本项目将氧化石墨烯（GO）、上转换纳米颗粒（UCNPs）、硫化亚铁（FeS2）等与贵金属纳米颗粒组装制备了多种手性纳米组装结构，发展手性纳米结构调控技术，建立了外场（电场、磁场）调控增强手性纳米结构光学活性方法。1）利用手性FeS2与氨基酸共组装形成水凝胶。研究发现采用偏振光能够调制凝胶体系的手性纳米结构，从而产生光学活性、荧光等光谱信号的变化，这为新型光学活性纳米探针的制备和性能调控提供了新的思路和方法。2）利用石墨烯与金纳米粒子的组装形成具有圆二色光谱（CD）和拉曼信号响应的高灵敏纳米探针，实现了肿瘤细胞从“外“到“内”的精确测定。3）针对细胞内成分的动态分析，制备了手性组装体由Au NR@Pt 二聚体与UCNPs形成卫星式组装结构，该探针在600–1000 nm范围内具有强吸收。在808nm下的圆偏振光照射下，当局部温度超过dsDNA的解链温度时， Zn2+/Mg2+/Cu2+响应发夹结构陆续打开，实现活细胞中3种金属离子的动态分析。