Dual-channel emission probe for monitoring biothiols and H2S in various scenarios: Living cells, plants, and food

Hydrogen sulfide (H2S) and biothiols, such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy), are involved in many physiological processes and important functions in living organisms. Moreover, H2S is a mediator of plant resistance to abiotic stress and is an indicator of food spoilage. The simultaneous discrimination of H2S, GSH, Cys, and Hcy is challenging because of their similar structures and reactivity. Herein, a dualchannel fluorescent probe, HBTMS, is fabricated by linking two potential fluorophores via ether bonds. The responses of HBTMS to GSH, Cys/Hcy, and H2S display diverse signal patterns, including red fluorescence for GSH, H2S, Cys, and Hcy under 380 nm excitation, green fluorescence for Cys and Hcy under 475 nm excitation, and colorless to purple colorimetric change only for H2S, providing a simple method for simultaneous detection and differentiation of GSH, Cys/Hcy, and H2S. Importantly, HBTMS successfully imaged GSH, H2S, and Cys/Hcy in HepG2 cells and plant roots under heavy metal stress, and revealed that oxidative stress induced by Cu, Zn, Mn, and Cr stress could upregulated GSH/H2S and Cys/Hcy levels in plant roots. In addition, utilizing both colorimetric and solid-state fluorescence, we employed HBTMS-loaded paper strips for the semi-quantitative detection of H2S gas and qualitative identification of food freshness.