Dual-channel fluorescent probe for detecting SO2 and Hg2+, and dynamic imaging SO2 under Cd2+ in alfalfa (Medicago sativa).

As an antioxidant, SO 2 plays a critical role in maintaining the plant's redox balance. At the same time, Hg2+ as heavy metals, will accumulate in plants through soil, often disrupting physiological processes in plants. However, few studies have been reported to examine changes in Hg2+ and SO 2 in plants. Here, we developed a dual-channel fluorescent probe NYD, which can differentiate between the detection of Hg2+ and SO 2. The probe exhibits high sensitivity (LOD, 44 nM for Hg2+ and 26 nM for SO 2). When Hg2+ and HSO 3 − deprotect and attack the double bond by nucleophilic addition, significant emission of fluorescence at 475 nm and 574 nm with blue and red fluorescence respectively. In addition, NYD has the capability to detect the levels of Hg2+ and SO 2 in cells and alfalfa seedlings. Meanwhile, the findings indicated that alfalfa seedlings were exposed to Cd2+, which led to redox imbalance and increased endogenous SO 2 production. We anticipate that this research will contribute to a better understanding of the functions of SO 2 under oxidative stress induced by Cd2+. We developed a dual-channel fluorescent probe NYD, which detects Hg2+ and SO 2 by turning on the ICT effect and Michael addition reaction, respectively. The probe has a significant fluorescence enhancement at the emission wavelength of 574 nm and 475 nm, respectively, with a detection limit of 44 nM and 26 nM, and has good selectivity for Hg2+ and SO 2. We successfully applied it to the detection of Hg2+ and SO 2 levels in cells. Furthermore, Hg2+ and SO 2 in alfalfa seedlings were detected by imaging technique, and the up-regulation of SO 2 under Cd2+ stress was verified. [Display omitted] • NYD shown dual-emission wavelength for monitoring Hg2+ and SO 2 , respectively. • Hg2+ and SO 2 levels in HepG2 cell and plant were tracked using NYD. • NYD detected the up-regulation of SO 2 in alfalfa seedlings under Cd2+ stress. [ABSTRACT FROM AUTHOR]