"Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley 41 A, 700487 Iasi, Romania.
Alexandru Ioan Cuza University of Iasi, Chemistry Department, 11 Carol I, 700506 Iasi, Romania.
Molecules. 2020 Sep 24;25(19):4397. doi: 10.3390/molecules25194397.
We have designed and synthesized a series of novel, supramolecular, long-lived fluorescent probes based on the host-guest inclusion complexes formation between fluorescent indolizinyl-pyridinium salts and β-cyclodextrin. Fluorescence and electrospray ionisation mass spectrometry experiments, supported by theoretical molecular docking studies, were utilized in the monitoring of the inclusion complexes formation, evidencing the appearance of corresponding 1:1 and 1:2 species. Additionally, the influence of the guest molecule over the aggregation processes of the cyclodextrin inclusion complexes was investigated by transmission electron microscopy. The absence of cytotoxicity, cellular permeability, long-lived intracellular fluorescence, and in time specific accumulation within acidic organelles identified the investigated supramolecular entities as remarkable candidates for intracellular fluorescence probes. Co-staining experiments using specific organelle markers revealed the fact that, after a 24-h incubation period, the inclusion complexes accumulate predominantly in lysosomes rather than in mitochondria. This study opens new possibilities for a broad range of fluorescent dyes with solubility and high toxicity issues, able to form inclusion complexes with β-cyclodextrin, to be tested as intracellular fluorescence probes.
我们设计并合成了一系列基于荧光吲哚嗪-吡啶盐与β-环糊精之间主客体包合复合物形成的新型超分子长寿命荧光探针。荧光和电喷雾电离质谱实验，辅以理论分子对接研究，用于监测包合复合物的形成，证明了相应的 1:1 和 1:2 物种的出现。此外，通过透射电子显微镜研究了客体分子对环糊精包合复合物聚集过程的影响。所研究的超分子实体具有无细胞毒性、细胞通透性、长寿命细胞内荧光以及在酸性细胞器中的时间特异性积累等特点，这表明它们是细胞内荧光探针的候选者。使用特定细胞器标记物的共染色实验表明，在 24 小时孵育后，包含复合物主要积累在溶酶体中，而不是线粒体中。这项研究为具有溶解度和高毒性问题的广泛的荧光染料开辟了新的可能性，这些染料能够与β-环糊精形成包合复合物，作为细胞内荧光探针进行测试。
