A Ratiometric Fluorescent Probe with Reversible Redox-Response for Monitoring Dynamic Release of H<sub>2</sub>S Donors
Yanxi Liu, Qu Tang, Yuming Zhang, Mengjia Xu, Yong Yao, Yuling Qin, Quan Liu, Li Wu
Abstract
It is of great importance to monitor H 2 S levels dynamically over an extended period in living systems. Despite the numerous H 2 S fluorescent probes that have been reported for biological imaging, only a few are reversible and capable of dynamic tracking. Given the potential impact of extraneous factors on fluorescence intensity, self-calibrating ratiometric probes are the preferred choice. In this study, we present a ratiometric probe named DaCou, which is based on the FRET mechanism. This probe can selectively and reversibly respond to H 2 S, with the maximal emission shifting between 595 and 476 nm. The FRET process transitions between on and off states during the absence and presence cycles of HS – . Additionally, the absorption band centered at 482 nm undergoes a corresponding cyclic decrement and increment. Mass spectrometry and nuclear magnetic resonance analysis confirmed the hydrogenation reduction of the energy acceptor component in DaCou by HS – . The reduced product, H 2 DaCou, can be reoxidized to DaCou by O 2 . The ratiometric and reversible imaging of HS – concentration changes has been successfully achieved in both HeLa cells and zebrafish embryos. Furthermore, DaCou was applied to visualize the release kinetics of slow-releasing H 2 S donors within cellular environments. Leveraging the advantages of ratiometric signaling, a comparable release kinetics was observed for SFN and GYY4137 at their respective concentrations that inhibit HeLa cells by 50%. This work provides a viable tool for the accurate and dynamic monitoring of H 2 S levels within living cells, which can assist in predicting the anticancer efficacy of H 2 S donors.