Inspired by the mechanism of aggregation induced emission, two derivatives of thiazole orange (TPE-mTO and Ph-TO) were rationally designed and prepared in this work. Their selectivity and sensitivity towards G-quadruplex were studied by fluorescence titration, gel analysis, and circular dichroism (CD) experiments. TPE-mTO could selectively lights-up G-quadruplex DNA structures with no conformational transition, while Ph-mTO could not distinguish the G-quadruplex DNA structure from other nucleic acid, which probably owing to the pocket size and shape of the G-quadruplex DNA only could hinder the rotation of TPE moiety. Then the speculation was verified by molecular docking, TPE-mTO could adopt an appropriate pose in 3′ and 5′ binding pockets of CM22 (G-quadruplex), the multiple interaction between TPE-mTO and CM22 do hinder the rotation of TPE moiety and lead to strong fluorescence. In addition, the detection limit (DL) of TPE-mTO towards CM22 (prefolded G-quadruplex) was found as low as 4.1 nM. With the help of TPE-mTO, the G-quadruplex DNA structures in mitochondrion can be easily and quickly tracked without further washing operations. Overall, the probe we developed (TPE-mTO) was a simple but powerful tool for studying G-quadruplex structures.

受聚集诱导发射机理的启发，本工作合理设计并制备了噻唑橙的两种衍生物（TPE-mTO和Ph-TO）。通过荧光滴定，凝胶分析和圆二色性（CD）实验研究了它们对G-四链体的选择性和敏感性。TPE-mTO可以选择性地点亮G-四链体DNA结构而没有构象过渡，而Ph-mTO不能将G-四链体DNA结构与其他核酸区分开，这可能是由于G-四链体的口袋大小和形状DNA仅会阻碍TPE部分的旋转。然后通过分子对接TPE-mTO验证了这一推测可以在CM22（G-四链体）的3'和5'结合口袋中采取合适的姿势，TPE-mTO和CM22之间的多重相互作用确实阻碍了TPE部分的旋转并导致强荧光。此外，发现TPE-mTO对CM22（预折叠的G-四链体）的检测限（DL）低至4.1 nM。借助TPE-mTO，无需进一步洗涤即可轻松，快速地追踪线粒体中的G-四链体DNA结构。总体而言，我们开发的探针（TPE-mTO）是研究G-四链体结构的简单但功能强大的工具。