Intracellular polarity is an essential feature of cell physiological state and abnormal polarity changes of various organelles are related to many diseases. Thus, monitoring of polarity changes of multiple subcellular in living cells contributes to understanding different physiological and pathological processes more accurately. However, most of the previous reports on polarity probes mainly monitored the polarity of a single organelle. Therefore, we designed and synthesized two unique polarity-sensitive fluorescent probes LDs-TPFP and Lyso-TPFP, which can be selectively located in lipid droplets (LDs) and lysosomes respectively, to obtain more subcellular information in living cells. Thanks to the strong intramolecular-charge-transfer (ICT) characteristics of probes, the fluorescence intensity and emission wavelength would change with the polarity of the surroundings of cells. Moreover, LDs-TPFP and Lyso-TPFP exhibits large Stokes shift and excellent biocompatibility. Through fluorescence imaging, the probes can effectively distinguish normal cells from cancer cells. In addition, the results of two-photon confocal fluorescence imaging indicated that LDs and lysosomes have discrepant polarity change behaviors under different physiological conditions.

中文翻译：

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双光子荧光探针同时监测脂滴和溶酶体的极性变化

细胞内极性是细胞生理状态的一个基本特征，各种细胞器的异常极性变化与许多疾病有关。因此，监测活细胞中多个亚细胞的极性变化有助于更准确地了解不同的生理和病理过程。然而，以前关于极性探针的大多数报告主要监测单个细胞器的极性。因此，我们设计并合成了两种独特的极性敏感荧光探针LDs-TPFP和Lyso-TPFP，它们可以分别选择性地定位在脂滴（LDs）和溶酶体中，以获得更多的活细胞亚细胞信息。由于探针具有强大的分子内电荷转移 (ICT) 特性，荧光强度和发射波长会随着细胞周围极性的变化而变化。此外，LDs-TPFP 和 Lyso-TPFP 表现出较大的斯托克斯位移和优异的生物相容性。通过荧光成像，探针可以有效区分正常细胞和癌细胞。此外，双光子共聚焦荧光成像结果表明，LDs 和溶酶体在不同生理条件下具有不同的极性变化行为。