基于BODIPY的光活化探针及其在超高分辨荧光成像中的研究

In recent years, super-resolution fluorescence microscopy techniques based on the localization of individual switchable fluorescent molecules have been invented to overcome the diffraction barrier. Photoactive rhodamines and fluoresceins already found their extensive use in biological research employing single molecular super-resolution fluorescence microscopy. Enhanced biocompatibility and resolution are two of the challenges faced by researchers. Actually, the spatial and temporal resolution of super-resolution microscopy will benefit from new fluorescent probes with brighter emission, higher photostability, higher on-off contrast. BODIPY might be a particularly useful scaffold in single molecular super-resolution fluorescence microscopy owing to its high absorptivity, excellent fluorescence properties and photostability. In this project, we will improve the biocompatibility by lowering the activation energy, when we are carrying an oxygen-involved photoactivation mechanism. Finally, the best series of photoactive BODIPY will be labeled to SNAP tag fusion epidermal growth factor receptor. Comparing the photon number, labeling density, localization precisions of photoactive BODIPY with photoactive rhodamine and fluorescein in experiments, we will reveal the potential of BODIPY dyes in single molecule imaging.

单分子超高分辨成像技术利用具有光开-关性质的探针，将荧光成像的分辨率提高至单个分子水平，引起了国内外生物与化学领域的广泛关注。其中，光活化有机探针展现出在单分子定位超高分辨成像中的巨大潜力，进一步提高成像分辨率，并增强生物相容性是光活化探针在活细胞成像中面临的两个挑战。为了增加探针光子数，降低背景荧光，提高成像分辨率，本项目选用消光系数大，荧光量子产率高，光稳定性好的BODIPY染料为研究对象。为了提高生物相容性，项目引入氧气协同的光活化机制，延长活化光波长，降低光损伤。最后，我们采用SNAP-tag标记方法实现表皮生长因子受体蛋白的特异性标记，考察光活化BODIPY探针成像的光子数，标记密度，定位精度等参数，阐明该研究方法在活细胞单分子定位超高分辨成像中研究前景。

光活化探针在单分子定位超高分辨荧光显微镜中的使用，使生物成像的精度可推进到几个纳米，受到国内外科研工作者的关注。针对目前单分子成像中活化波长短，且需要使用大量β巯基乙醇辅助荧光淬灭等问题，本项目基于BODIPY、萘酰亚胺、芘、锌取代Salen、硅取代派若宁等发光团，引入光反应位点，合成系列衍生化合物，测定其光物理性质和光活化性能，成功得到3例性质优良的光活化探针，它们分别具有可见光活化，谷胱甘肽淬灭，双波长光转换等优点。细胞成像结果表明，3例探针都具有良好的水溶性和生物相容性：细胞毒性低，细胞渗透性好，光活化效率高，可应用于单分子定位超高分辨成像中。