Near-infrared fluorescent probe with a self-immolative spacer for ratiometric imaging alkaline phosphatase in cell and zebrafish

Abstract

Alkaline phosphatase (ALP), as a vital hydrolase, abnormal level can cause tissue damage and induce several diseases. Therefore, it is regarded as an important biomarker in clinical diagnostic medicine. Herein, we developed a highly selective and sensitive near-infrared (NIR) ratiometric fluorescent probe (YJ) for real-time monitoring of ALP activity in vitro and vivo. Notably, as reported so far, YJ has the shortest response time (within 5 min) among the NIR ratiometric ALP fluorescent probes. In addition, YJ shows exceptional fluorescence properties such as a large Stokes shift (160 nm), low detection limit (2.36 U L−1), the ratiometric determination of ALP at 570 nm and 667 nm, low cytotoxicity and strong anti-interference ability. Moreover, we not only successfully detected the level of endogenous ALP in living cells with YJ, but also tracked and monitored the spatial localization of endogenous ALP activities in zebrafish caused by APAP-induced organ damage.