A mitochondria-targetable fluorescent probe for ratiometric detectionof SO2 derivatives and its application in live cell imaging

A fluorescent probe (DBT) based on conjugation of 2,3-dimethylbenzo[d] thiazol-3-ium iodide to 3-(benzo[d] thiazol-2-yl)-2-hydroxy-5-methylbenzaldehyde for the detection of sulfur dioxide derivatives(HSO3/SO32) has been developed. DBT exhibits highly selective colorimetric and ratiometric fluorescence dual response to HSO3- with a fluorescence detection limit of 3.50 x 10(-7) M. The HSO3 - sensing mechanism was confirmed to undergo nucleophilic addition of HSO3- to alkene double bond of DBT as evidenced by H-1 NMR and HRMS analysis. The probe is MCF-7 cell permeable and applicable for fluorescence imaging of exogenous and intrinsically generated intracellular SO2 derivatives in the living cells. Fluorescence co-localization studies reveal that DBT is a mitochondria-targetable fluorescent probe. Thus, DBT has potential application for exploring the role played by SO2 derivatives in biology. (C) 2017 Elsevier B.V. All rights reserved.