Dong Zhe, Han Qingxin, Mou Zuolin, Li Ge, Liu Weisheng
Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China.
J Mater Chem B. 2018 Mar 7;6(9):1322-1327. doi: 10.1039/c7tb03089d. Epub 2018 Feb 9.
Lysosomal pH is known to be acidic, which plays a vital role in various processes in living organisms. Frequency upconversion luminescence exhibits the unique ability to convert low energy photons into high energy photons, which can be used in live samples due to its deep penetration, low tissue damage, etc. The development of sensitive frequency upconversion probes with a low pK, high sensitivity, and specific selectivity for lysosomal pH detection is of great importance. Herein, we report a novel frequency upconversion luminescence probe, NRH-Lyso, by conjugating the rhodamine derivative NRH and the lysosome targeting functional group 4-(2-aminoethyl)morpholine. NRH-Lyso shows a sensitive response to acidic pH and excellent selectivity in the presence of metal ions, anions, and small molecules. Due to the structural transformation of lactam ring opening and closing of NRH-Lyso, the probe shows an almost 80-fold enhancement in emission intensity when the pH changes from 7.0 to 4.0 under 808 nm laser excitation. The living cell imaging data reveals that NRH-Lyso can selectively detect lysosomal pH changes with excellent photostability and low cytotoxicity. All these features make NRH-Lyso a good candidate to investigate the lysosomal pH-associated physiological and pathological processes.
已知溶酶体的pH呈酸性，这在生物体的各种过程中起着至关重要的作用。频率上转换发光具有将低能量光子转换为高能量光子的独特能力，由于其穿透深度深、对组织损伤小等特点，可用于活样本。开发具有低pK、高灵敏度和对溶酶体pH检测具有特异性选择性的灵敏频率上转换探针具有重要意义。在此，我们通过将罗丹明衍生物NRH与溶酶体靶向官能团4-(2-氨基乙基)吗啉共轭，报道了一种新型频率上转换发光探针NRH-Lyso。NRH-Lyso在存在金属离子、阴离子和小分子时对酸性pH表现出灵敏响应和优异的选择性。由于NRH-Lyso的内酰胺环开环和闭环的结构转变，在808 nm激光激发下，当pH从7.0变为4.0时，该探针的发射强度增强了近80倍。活细胞成像数据表明，NRH-Lyso能够以优异的光稳定性和低细胞毒性选择性地检测溶酶体pH的变化。所有这些特性使NRH-Lyso成为研究溶酶体pH相关生理和病理过程的良好候选者。
