分子光开关用于嵌段共聚物自组装纳米结构的超分辨荧光成像

Self-assembly of block copolymers produces microphase separation and periodic nanostructures, which are generally characterized by TEM, SEM or AFM. Recently, a super-resolution fluorescent imaging method was developed based on high-accurate localization of single photoswitchable fluorophore, which can surmount the optical diffraction limit affording nanoscale optical resolution down to several nanometers. Based on the mechanism of stochastic optical reconstruction microscopy (STORM) or photo-activated localization microscopy (PALM), this project is to develop novel fluorescent molecular switches with optimal optical switching and compatibility to block copolymers, construct a library of fluorescent molecular switches for super-resolution imaging, optimize the specific super-resolution imaging probes for various block copolymers and conduct the super-resolution imaging experiments of self-assembled nanostructures of block copolymers to improve the optical imaging resolution. Inspired by the success application of super-resolution imaging in subcellular nanostructures, we hope that the multidisciplinary integration of chemistry and optical science would provide 20 nm of imaging resolution for self-assembled nanostructures of block copolymers.

嵌段共聚物自组装纳米结构，其形貌和尺寸通常采用电镜或原子力显微镜进行 表征。近年来人们发展了一种基于单分子光开关荧光探针高准确定位的超分辨荧光显微技 术，可突破光学衍射极限，分辨率达到纳米尺度（最低至几个纳米）。本研究基于随机光学 图像重构（Stochastic optical reconstruction microscopy，STORM）或光活化定位显 微术（Photo-activated localization microscopy, PALM）的基本原理，发展新兴荧光分 子开关，对这些新型荧光分子开关进行分子相容性及光学开关优化，建立起一套适用于超分 辨显微成像的荧光开关分子探针库，研究可用于不同嵌段共聚物的特异性超分辨成像探针，并对不同嵌段共聚物自组装纳米结构进行超分辨光学成像，将光学成像分辨率提高至20 纳米尺度，实现嵌段共聚物的纳米级光学分辨表征。

当前基于单分子定位原理的超分辨光学成像技术主要集中应用于生物体系细胞亚细胞结构和功能的研究，难以直接应用于非生物体系，使得材料科学领域缺乏纳米级分辨率的光学表征方法。本项目建立和发展了基于有机荧光分子开关的超分辨成像技术，它能够适用于非生物体系的超分辨成像。本项目以嵌段共聚物自组装纳米结构为研究载体，使用优化后的有机荧光分子开关及聚集诱导发光探针染色，通过光照刺激或者动态相互作用，诱导纳米材料内部或表面产生随机的荧光开关行为，最终实现超分辨荧光成像，获得30-100纳米的超分辨率，突破了光学衍射极限，证明了有机荧光分子开关作为一种新型超分辨成像探针能够实现以嵌段共聚物为代表的软物质的光学纳米成像，具有广泛的应用前景和实用价值。