Near-infrared (NIR) absorption and fluorescence sensing of reactive Sulfur species in drug-induced liver injury.

Drug induced liver injury (DILI) is a major cause of acute liver injury, and accumulating evidence has confirmed a close correlation between endogenous RSS levels and the progression of DILI. Therefore, it is crucial to develop fluorescence sensor to investigate the RSS signal changes in living organisms. In this work, a novel NIR fluorescent probe PMI-CD-NBD with integrated absorption and emission properties was developed. PMI-CD-NBD exhibited distinct RSS-triggered fluorescence enhancement toward H2S, L-Cys, GSH and L-Hcy both in vitro and in vivo, which is attributed to a selective nucleophilic substitution reaction mechanism. The calculated detection limits of PMI-CD-NBD for H2S, L-Cys, GSH, and L-Hcy were 9.25 nM, 5.43 nM, 10.54 nM, and 7.01 nM, respectively. Benefiting from its excellent sensing performance, PMI-CD-NBD enables noninvasive and accurate imaging of endogenous RSS fluctuations in APAP-induced liver injury models. As a reliable NIR fluorescent platform, PMI-CD-NBD demonstrates great potential for endogenous RSS detection, serving as a promising bioanalytical tool for the diagnosis and evaluation of DILI.