A simple fluorescent probe for biothiols detection and imaging of living cells in vivo based on a hemicyanine derivative

Biothiols play essential roles in various biological processes and are closely associated with diseases such as cancer, neurodegenerative disorders, cardiovascular diseases and so on. To monitor biothiols in organisms and living cells, we present the synthesis of a novel intramolecular charge transfer (ICT)-based probe, HCD, by coupling a hemicyanine dye with 2,4-dinitrobenzenesulfonyl chloride. The HCD exhibits remarkable sensitivity, with a low detection limit of 0.32µM, 0.72µM and 0.27 µM for Cys, Hcy, and GSH, respectively, and demonstrates high selectivity for biothiols in the presence of various interfering species. The detection mechanism was thoroughly validated using high-resolution mass spectra (HRMS), UV and fluorescence spectra. Moreover, the applicability of HCD was successfully demonstrated in human urine samples and in vivo settings using RAW264.7 cells, confirming its potential as a powerful tool for monitoring endogenous biothiols in biological systems.