Intracellular pH plays a significant role in many pathological and physiological processes. A series of quinoline-pyrene probes were synthesized in one-step fashion through an oxonium-ion-triggered alkyne carboamination sequence involving C-C, C-O and C-N bond formation for intracellular pH sensing. The quinoline-pyrenes showed significant red shifts at low pH. Fluorescence lifetime decay measurements of the probes showed decreases in lifetime at pH 4. The probes showed excellent selectivity in the presence of various potential interfering agents such as amino acids and cations/anions. Furthermore, the probes were found to show completely reversible emission behaviour in the window between pH 4 and 7. A morpholine-substituted quinoline-pyrene probe efficiently stained lysosomes with high Pearson correlation coefficients (0.86) with Lysotracker Deep Red DND-99 as a reference. A co-localization study of the probe with Lysotracker DND-99 showed selective intracellular targeting and a shift in fluorescence emission due to acidic lysosomal pH.

中文翻译：

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靶向溶酶体pH的基于喹啉-Ratio的比例荧光探针的设计和快速合成。

细胞内pH在许多病理和生理过程中起着重要作用。通过含氧离子触发的炔烃碳氨化序列，涉及CC，CO和CN键的形成，以一步法合成一系列喹啉-py探针，用于细胞内pH传感。喹啉-吡啶在低pH下显示出明显的红移。探针的荧光寿命衰减测量结果表明，在pH 4时寿命降低。在存在各种潜在干扰剂（例如氨基酸和阳离子/阴离子）的情况下，探针表现出出色的选择性。此外，发现探针在pH 4和7之间的窗口中显示出完全可逆的发射行为。吗啉取代的喹啉-探针有效地染色了具有高Pearson相关系数的溶酶体（0。86），并以Lysotracker深红色DND-99作为参考。探针与Lysotracker DND-99的共定位研究表明，由于酸性溶酶体pH值，选择性细胞内靶向和荧光发射发生变化。