A novel 2-aminophenalenone-based fluorescent probe designed for monitoring H 2 O 2 for in vitro and in vivo bioimaging

A significant compound in living organisms, hydrogen peroxide (H O ) plays a dual role as a signalling molecule in cellular communication and as a pivotal biomarker in assessing disease and oxidative stress. Thus, the detection of abnormal changes in H O levels is essential to understanding its function and involvement in biological systems. The growing demand to meet the specific needs for applications, particularly in biological systems, has sharpened focus on highly sensitive, highly selective molecular sensors and, in turn, heightened interest in these diagnostic tools with innovative designs. In our study, 2-aminophenalenone (2-AP) was used for the first time as a fluorophore in a fluorescent probe. The 2-APB molecule obtained from the reaction of 2-AP with 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzyl chloroformate exhibited a highly selective and sensitive (i.e. 62 nM) detection profile for H O compared with the other reactive oxygen species, anions, and metal cations. Moreover, offering naked-eye detection in aqueous solutions, 2-APB demonstrated excellent sensing performance, detection and real-time monitoring in relation to exogenous H O in cells and endogenous H O in zebrafish embryos.