Zhou Jin, Fang Canliang, Chang Tianjun, Liu Xiangjun, Shangguan Dihua
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
J Mater Chem B. 2013 Feb 7;1(5):661-667. doi: 10.1039/c2tb00179a. Epub 2012 Nov 27.
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.
细胞内和细胞外的pH值在许多细胞生物学过程中起着关键作用。同时监测活细胞内外pH值变化的探针很少见。在本文中，我们描述了一种新的比率型pH荧光团，它是由4-溴-1,8-萘二甲酰亚胺和3-氨基-1,2,4-三唑缩合而成。在pH 5-8范围内，该荧光团杂环稠合芳香环系统中唯一的N-H发生可逆的去质子化-质子化过程，导致吸收光谱和发射光谱发生较大的红移。在水溶液中，该荧光团在酸性和碱性形式下均表现出良好的pH选择性、高光稳定性、高离子强度耐受性和高荧光量子产率。设计了该荧光团的一种长链衍生物（HNNA）用于细胞pH传感。发现HNNA定位于细胞的膜结构上，并通过共聚焦成像成功用于绘制细胞外微环境和细胞内的pH变化图。
