A highly effective turn-on tanshinone IIA-based fluorescent probe for rapid and sensitive detection of ClO- and its application in environmental analysis and bioimaging

Hypochlorite (ClO-) is an important reactive oxygen species, which is closely related to many physiological processes and diseases, and plays a crucial role in the innate immune system against invasive microorganisms. However, excess ClO- level can cause oxidative stress and cell damage, so it is of great significance to detect ClO- in environmental samples and living systems. Tanshinones, a type of natural phenanthraquinones containing a large conjugating structure, could be a promising precursor for constructing new fluorescent probes. In this paper, a novel tanshinone IIA-based off-on fluorescent probe TPD was developed for monitoring ClO- in vitro and in vivo. The probe TPD could detect ClO- with favorable selectivity and the limit of detection was 34.3 nM. TPD exhibited rapid response (20 s) and extensive pH detection range (4 similar to 9) towards ClO- . What is more, the detection mechanism was studied by H-1 NMR titration, HRMS and density functional theory (DFT) calculations. Based on the above eminent performances, TPD was successfully applied to trace ClO- in environmental water samples, living cells and zebrafishes, and the TPD-loaded test strips were also prepared for rapid identification of ClO-.

Automated summary

A novel tanshinone IIA-based off-on fluorescent probe TPD was developed for monitoring hypochlorite (ClO-) in vitro and in vivo. The probe TPD exhibited favorable selectivity with a limit of detection of 34.3 nM, rapid response (20 s) and extensive pH detection range (4 to 9) towards ClO-. The detection mechanism was studied by H-1 NMR titration, HRMS and density functional theory (DFT) calculations. TPD was successfully applied to trace ClO- in environmental water samples, living cells, and zebrafishes, and TPD-loaded test strips were prepared for rapid identification of ClO-.