Visualization of peroxynitrite/GSH cross-talk in the oxidant–antioxidant balance by a dual-fluorophore and dual-site based mito-specific fluorescent probe

Peroxynitrite (ONOO−) and glutathione (GSH) play mutually regulating roles in the oxidant–antioxidant balance of organisms, which has a profound relationship with people's health and disease. In this study, we designed a two-photon fluorescent probe CD-NA that could simultaneously detect ONOO− and GSH via dual-fluorophore and dual-site properties. CD-NA shows different fluorescence responses to ONOO− (annihilated red fluorescence) and GSH (enhanced green emission) with high specificity and sensitivity. Notably, the response of CD-NA to ONOO− was unaffected by GSH, and the reverse is also true. It allows the ONOO−/GSH cross-talk to be successfully imaged. Given these excellent properties, CD-NA has been favorably employed in detecting ONOO− and GSH in living cells with the ability to target mitochondria. Therefore, CD-NA offers an efficient method for understanding the oxidant–antioxidant balance and interrelated physiological functions of ONOO− and GSH in living systems, and provides a new strategy to sort out the complex relationships and roles of various analytes in complex physiological processes.