A pH sensitive ratiometric fluorophore and its application for monitoring the intracellular and extracellular pHs simultaneously
作者:Jin Zhou、Canliang Fang、Tianjun Chang、Xiangjun Liu、Dihua Shangguan
DOI:10.1039/c2tb00179a
日期:——
Intracellular and extracellular pH plays a key role in many cell biological processes. Probes for simultaneously monitoring the pH change inside and outside living cells are rarely available. In this paper, we describe a new ratiometric pH fluorophore that was synthesized by condensation of 4-bromine-1,8-naphthalimides and 3-amino-1,2,4-triazole. In the range of pH 5–8, the only N–H in the heterocycle-fused aromatic ring system of this fluorophore undergoes a reversible deprotonation–protonation process, which results in a large red shift of the absorption and emission spectra. In aqueous solution, this fluorophore exhibits good pH selectivity, high photostability, high tolerance to ionic strength, and high fluorescence quantum yield in both the acid and base forms. A long chain derivative of this fluorophore (HNNA) was designed for cellular pH sensing. HNNA was found to locate on the membrane structure of the cells, and was successfully used for mapping the pH change in both the extracellular microenvironment and the inner cells by confocal imaging.
细胞内外的 pH 值在许多细胞生物过程中发挥着关键作用。目前很少有探针能同时监测活细胞内外的 pH 值变化。在本文中,我们介绍了一种新的 pH 计比率荧光团,它是由 4-溴-1,8-萘二甲酰亚胺和 3-氨基-1,2,4-三唑缩合合成的。在 pH 值为 5-8 的范围内,这种荧光团的杂环融合芳环系统中唯一的 N-H 发生可逆的去质子化-质子化过程,从而导致吸收和发射光谱发生较大的红移。在水溶液中,这种荧光团具有良好的 pH 选择性、高光稳定性、对离子强度的高耐受性,并且在酸性和碱性形式下都具有高荧光量子产率。这种荧光团的长链衍生物(HNNA)被设计用于细胞 pH 值传感。研究发现,HNNA 可定位在细胞膜结构上,并通过共聚焦成像技术成功绘制了细胞外微环境和细胞内 pH 值变化图。