A lysosome specific, pH tolerant, and polarity sensitive fluorescent probe (LyPol) is designed and synthesized for the determination of lysosomal polarity in live cells. LyPol possesses an intramolecular charge transfer (ICT) properties with high quantum yield in water and in other polar solvents such as methanol, ethanol, dimethyl sulfoxide, acetonitrile etc. The fluorescence maxima and lifetime increase linearly with a non-specific manner with an increase in the polarity of its surrounding environment. A morpholine group connected with an alkyl linker acts as a lysosome directing moiety, which is attached with the fluorescent core of LyPol. The selective localization of LyPol inside the lysosome was confirmed with live-cell confocal imaging. Further, the spectral scanning confocal technique was utilized to determine the emission spectrum of LyPol inside lysosome and the polarity turns out to be quite lower as compared to water. Moreover, the combined spectroscopic, and live-cell microscopy confirms that the interior of the lysosome is significantly non-polar in cancer cell compared to normal cells. We believe that this report on the measuring polarity inside the biological system with a solvatofluorochromic probe will be of immense interest to researchers working in the multidisciplinary area of biophysics, microscopy, chemical biology and organelle biology.

设计并合成了一种溶酶体特异性、pH 耐受性和极性敏感的荧光探针 ( LyPol )，用于测定活细胞中的溶酶体极性。 LyPol具有分子内电荷转移 (ICT) 特性，在水和其他极性溶剂（如甲醇、乙醇、二甲基亚砜、乙腈等）中具有高量子产率。随着荧光强度的增加，荧光最大值和寿命以非特异性方式线性增加。周围环境的极性。与烷基连接体连接的吗啉基团充当溶酶体导向部分，与LyPol 的荧光核心相连。活细胞共聚焦成像证实了LyPol在溶酶体内的选择性定位。此外，利用光谱扫描共焦技术确定了溶酶体内LyPol的发射光谱，结果表明与水相比，极性要低得多。此外，结合光谱和活细胞显微镜证实，与正常细胞相比，癌细胞中的溶酶体内部显着非极性。我们相信，这份关于用溶剂化荧光染料探针测量生物系统内部极性的报告将对生物物理学、显微镜学、化学生物学和细胞器生物学等多学科领域的研究人员产生极大的兴趣。