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

Abstract

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 ∼ 9) towards ClO−. What is more, the detection mechanism was studied by 1H 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−.