Fluorescent probes based on benzothiazole-spiropyran derivatives for pH monitoring in vitro and in vivo

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Original languageEnglish
Article number117506
Journal / PublicationSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Online published2 Sep 2019
Publication statusPublished - 15 Jan 2020


In this study, by coupling benzothiazole and spiropyrans, three fluorescent probes HBT-pH 1, HBT-pH 2, and HBT-pH 3 were developed for pH variation monitoring. All these probes exhibited remarkable changes of absorption and emission accompanying its protonation under acidic conditions. HBT-pH 1 exhibited OFF-ON response when pH value was changed from 12.00 to 2.02, whereas ratiometric responses (large Stokes shifts) were obtained for HBT-pH 2 and HBT-pH 3. The response was attributed to the open-loop of spiropyran under acidic conditions, which was confirmed by 1H NMR. The pKa values of 6.57, 4.90, and 3.95 were obtained for HBT-pH 1, HBT-pH 2, and HBT-pH 3, respectively, indicating they were suitable for pH variation monitoring. Furthermore, low cytotoxicity and cell imaging of pH changes with HBT-pH 2 in living cells were successfully demonstrated, suggesting potential application in early diagnosis of pH-related diseases.

Research Area(s)

  • Benzothiazole, Fluorescent probe, In vivo, pH, Spiropyrans

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