A simple pyrene-hemicyanine fluorescent probe for colorimetric and ratiometric detection of SO2 derivatives in the mitochondria of living cells and zebrafish in vivo

A new ratiometric fluorescent probe IP based on pyrene-containing 1,2,3,3-tetramethyl-3H-indolium has been designed and synthesized for detecting SO2 in aqueous environment. The probe IP exhibited a dual colorimetric and ratiometric response toward SO32-/HSO3-. It displayed high selectivity towards SO32- within 30 s with a detection limit of 15.1 nM. A Michael addition reaction was proposed for the sensing mechanism of this probe, which was confirmed using H-1 NMR, C-13 NMR and ESI-MS spectra. Moreover, the probe IP could be applied to the mitochondria of HCC cells to detect SO32- through confocal fluorescence microscopy. Thus, this probe IP could monitor the transfer of SO2 in the mitochondria of living cells. Additionally, fluorescence imaging of SO32- in zebrafish was performed using the novel probe, suggesting its potential application in clinical diagnostics. (C) 2018 Elsevier B.V. All rights reserved.