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

Abstract

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 dual-channel 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.

Keywords: Biothiol; Food spoilage; Hydrogen sulfide; Imaging; Probe-loaded paper strips.