Design, synthesis and evaluation of a highly selective fluorescent probe for hypochlorous acid imaging in living...

Hypochlorous acid, as an important reactive oxygen species, plays a critical role in both physiological and environmental processes. However, excessive hypochlorous acid can induce cellular and tissue damage, which triggers various diseases including arthritis, atherosclerosis, neurodegenerative disorders and even cancer. In recent years, fluorescent probe technology characterized by high sensitivity and strong selectivity exerts its influence in analytical chemistry and life sciences. Most studies on hypochlorous acid-related fluorescent probe have primarily focused on the detection performance in chemical system and it's difficult to combine multiple advantages including reacting specifically and quickly. Moreover, as an important part of research and development, biosafety of probes is often ignored. In this study, we designed and synthesized a quenching-type fluorescent probe RD that exhibited specific responsiveness to hypochlorous acid. The response mechanism of probe RD was verified by NMR and HRMS. Furthermore, through kinetic analysis, quantitative fluorescence measurements and selectivity testing, we demonstrated that probe RD possessed superior optical properties and could sensitively and specifically detect hypochlorous acid. Note that we innovatively used transgenic zebrafish to establish a systemic evaluation system for biological safety. This system encompassed 14 toxicity indicators involving behavioral effects, cardiotoxicity, hepatotoxicity, nephrotoxicity and neurotoxicity, and the data confirmed the safety of probe RD in vivo. Additionally, we applied probe RD to both cultured cells in vitro and zebrafish in vivo for imaging experiments. By exogenously adding hypochlorous acid in varying concentrations and inducing endogenous hypochlorous acid production, we further verified its exceptional performance that probe RD could detect hypochlorous acid in cultured cells and zebrafish models. Thus, we developed a new fluorescent probe RD which could detect hypochlorous acid in biological systems, and created an evaluation system to study the biocompatibility which could be applied to relevant research.