Cysteine recognition by a benzothiazole-derived fluorescent probe with AIE plus ESIPT characteristics

A series of fluorescent dyes based on 2-(2'-hydroxyphenyl)benzothiazole derivatives were designed and synthesized. Because of their structural characteristics of AIE + ESIPT , they have long-wavelength emission and a larger Stokes shift. The fluorescent probe HBTN-Y was prepared based on the fluorescent dye HBTN. Probe HBTN-Y can recognize cysteine (Cys) with a high selectivity, OFF-ON fluorescence response, a large Stokes shift (263 nm) and long-wavelength emission (637 nm) in MeCN/H2O (1:1, v/v, PBS 20 mM, pH = 8.4) solution. The probe exhibits good anti-interference ability, a low detection limit of 6.51 x 10(-6) M, and is suitable for application at near neutral and weak alkaline pH (7-9) conditions. Moreover, HBTN-Y is applicable to image Cys in living MCF-7 cells.

Automated summary

In this study, a series of fluorescent dyes based on 2-(2'-hydroxyphenyl)benzothiazole derivatives were designed and synthesized, which exhibited long-wavelength emission and a larger Stokes shift due to their structural characteristics of AIE + ESIPT. A fluorescent probe, HBTN-Y, was prepared based on the fluorescent dye HBTN and showed high selectivity towards cysteine, with OFF-ON fluorescence response, a large Stokes shift, and long-wavelength emission in a specific solution. The probe demonstrated good anti-interference ability, low detection limit, and applicability for live cell imaging.