Mitochondria-targeted dual-channel colorimetric and fluorescence chemosensor for detection of Sn ions in aqueous solution based on aggregation-induced emission and its bioimaging applications.

Several fluorescence and colorimetric chemosensory for Sn detection in an aqueous media have been reported, but applications remain limited for discriminative Sn detection in live human cells and zebrafish larvae. Herein, a mitochondria-targeted Sn "turn-on" colorimetric and fluorescence chemosensor, 2CTA, with an aggregation-induced emission (AIE) response was developed. The sensing of Sn was enabled by a reduction-enabled binding pathway, with the conversion of -C˭O groups to -C-OH groups at the naphthoquinone moiety. The color changed from light maroon to milky white in a buffered aqueous solution. The chemosensor 2CTA possessed the excellent characteristics of good water solubility, fast response (less than 10 s), and high sensitivity (79 nM) and selectivity for Sn over other metal ions, amino acids, and peptides. The proposed binding mechanism was experimentally verified by means of FT-IR and NMR studies. The chemosensor 2CTA was successfully employed to recognize Sn in live human cells and in zebrafish larvae. In addition, a colocalization study proved that the chemosensor had the ability to target mitochondria and overlapped almost completely with MitoTracker Red. Furthermore, a bioimaging study of live cells demonstrated the discriminative detection of Sn in human cancer cells and the practical applications of 2CTA in biological systems.