Super-resolution fluorescence microscopy has emerged as a powerful tool for studying mitochondrial dynamics in living cells. However, the lack of photostable and chemstable probe makes long-term super-resolution imaging of mitochondria still a challenging work. Herein, we reported a 4-azetidinyl-naphthliamide derived SNAP-tag probe AN-BG exhibiting excellent fluorogenicity and photostability for long-term super-resolution imaging of mitochondrial dynamics. The azetidinyl group and naphthalimide fluorophore are in a flat conformation which can effectively suppress twisted intramolecular charge transfer and then effectively improve the brightness and photostability. This planarized molecular structure is conducive to the formation of fluorescence-quenched J-aggregates, and the protein labeling process will depolymerize the probes and restore fluorescence. Fluorescent labeling mitochondrial inner membrane proteins via SNAP tags overcomes the shortcomings that variations in mitochondrial inner membrane potential will release probes attached to mitochondria by electrostatic interactions. Therefore, AN-BG realized the stable labeling of mitochondria and the long-term imaging of mitochondrial dynamics under super-resolution microscopy.

超分辨率荧光显微镜已成为研究活细胞中线粒体动力学的强大工具。然而，缺乏光稳定和化学稳定的探针使得线粒体的长期超高分辨率成像仍然是一项艰巨的工作。在这里，我们报告了一个4-氮杂环丁烷基萘酰胺衍生的SNAP-tag探针AN-BG，对于线粒体动力学的长期超分辨率成像，具有出色的荧光性和光稳定性。氮杂环丁烷基和萘二甲酰亚胺荧光团为平面构型，可有效抑制分子内扭曲电荷的转移，并有效提高亮度和光稳定性。这种平面化的分子结构有利于荧光猝灭J的形成。-聚集，蛋白质标记过程将使探针解聚并恢复荧光。通过SNAP标签荧光标记线粒体内膜蛋白克服了线粒体内膜电位变化会通过静电相互作用释放附着于线粒体的探针的缺点。因此，AN-BG在超分辨率显微镜下实现了线粒体的稳定标记和线粒体动力学的长期成像。