Tan Jia-Lian, Zhang Mu-Xue, Zhang Fang, Yang Ting-Ting, Liu Yu, Li Zhu-Bo, Zuo Hua
College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China.
College of Resources and Environment, Southwest University, Chongqing 400715, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Apr 5;140:489-94. doi: 10.1016/j.saa.2014.12.110. Epub 2015 Jan 3.
A novel "off-on" colorimetric and fluorescent rhodamine analogue was synthesized and characterized, and used to monitor extreme acidity (below pH 3.5) via the photophysical response to pH. The colorless spirocyclic structure at high pH (pH⩾7.0) opened to the colored and highly fluorescent form at very low pH (pH<3.0). This sensitive pH probe was characterized with short response time, good reversibility and no interaction with interfering metal ions, and the quantitative relationship between the fluorescence intensity and pH value was consistent with the equilibrium equation pH=pKa-log[(Imax-I)/(I-Imin)]. The fluorescent response to strong acidity was further verified by fluorescent imaging of bacteria, Escherichia coli, which contributed to the development of more useful colorimetric and fluorescent sensors based on the rhodamine platform for measuring intracellular pH in extremely acidic conditions.
合成并表征了一种新型的“开-关”比色和荧光罗丹明类似物，并通过对pH的光物理响应来监测极端酸度（pH低于3.5）。在高pH（pH⩾7.0）下无色的螺环结构在极低pH（pH<3.0）下转变为有色且高荧光的形式。这种灵敏的pH探针具有响应时间短、可逆性好且与干扰金属离子无相互作用的特点，荧光强度与pH值之间的定量关系符合平衡方程pH = pKa - log[(Imax - I)/(I - Imin)]。通过对大肠杆菌进行荧光成像进一步验证了对强酸性的荧光响应，这有助于开发基于罗丹明平台的更实用的比色和荧光传感器，用于在极端酸性条件下测量细胞内pH。
