水分散性荧光聚合物量子点设计合成及多色可调光开关研究

Research on fluorescent nanomaterials with multicolor tunable and photoswitchable properties in fluorescent probes is an important field. However, such material systems with facile preparation and excellent performance are deficient now. In view of this, based on the principle of fluorescence resonance energy transfer (FRET), this project applies the new amphiphilic photochromic copolymer as matrix doped with a variety of fluorescent conjugated polymers (polyfluorene derivatives), to prepare the novel water-dispersible, nano-sized (ca. 10 nm) multicolor tunable and photoswitchable fluorescent polymeric quantum dots via coprecipitation method. The effect of structure, composition and size of the polymeric quantum dots on their optical properties is investigated and optimized to maximize the single particle fluorescence brightness. Study the FRET process between the chromophores as well as the change of FRET efficiency after light modulation in order to establish the corresponding relationship between the energy transfer efficiency with the proportion of the chromophores, so as to optimize the design of the proportion of the chromophores. By doing this, it intends to obtain a series of polymeric quantum dots with high single particle fluorescence brightness, adjustable multicolor under a single-wavelength excitation, high switching contrast, as well as long-term stability, at the same time to further expand the existing FRET application system, and to provide crucial scientific evidences for applying these fluorescent materials to the ultrahigh resolution multi-cellular imaging, labeling and recognizing of multi-component in complex biological systems and other biomedical fields.

兼具多色可调与光开关性能的荧光纳米材料是荧光探针研究发展的重要方向，目前制备便捷、性能优异的此类材料体系非常缺乏。鉴于此，本项目基于荧光共振能量转移（FRET）原理，以新型两亲性光致变色共聚物为基质掺杂多种荧光共轭聚合物（聚芴衍生物），利用共沉淀方法制备新型水分散性、纳米尺度（10nm左右）的多色可调光开关荧光聚合物量子点。探讨聚合物量子点结构组成及大小对其光学性能的影响并优化，最大限度提高单粒子荧光亮度。研究各生色团间的FRET过程及光调制下的FRET效率变化，建立能量转移效率与各生色团比例的对应关系，以优化生色团的比例设计，拟获得一系列具有高单粒子荧光亮度、单波长激发下多色可调、高开关对比度、长期稳定的聚合物量子点，进一步拓展现有FRET应用体系，为该类荧光材料在超高分辨率多细胞成像、复杂生物体系内多组分标记与识别等生物医学领域上的应用提供重要的科学依据。

以聚合物纳米粒子为基质的光开关荧光材料和荧光传感器材料在超分辨率生物成像、信息存储与加密、生物医学和传感等领域具有非常重要的应用价值而备受关注。本项目以荧光共振能量转移（FRET）原理为主要设计基础，采用可逆加成-断裂链转移-细乳液聚合、共沉淀、自组装和表面接枝等策略将能级匹配的功能性荧光染料共同结合到聚合物纳米粒子中，设计合成了一系列具有光开关/多色荧光聚合物纳米材料和荧光聚合物纳米粒子传感器，系统深入地探索了聚合物纳米粒子中各荧光团的配比及浓度与荧光信号变化的依赖关系、FRET作用机制与能量转移效率优化等问题，并将它们成功应用于光可逆擦写的图案印刷化、活细胞的可逆双色荧光成像，以及各种离子或生物分子的体外高灵敏度、高选择性荧光检测和细胞中实时成像分析。本项目所取得的成果将为智能荧光纳米材料的设计合成与生物传感和成像应用等方面提供新的思路和科学依据。项目原预期在国内外重要专业期刊上发表论文8-12篇，申请中国专利2-3项；实际发表SCI论文19篇（影响因子大于5的有13篇），国内期刊论文2篇，申请中国发明专利24项（其中已获授权10项），在成果方面超出了预期计划。