A superoxide anion activatable near-infrared fluorescent probe with a large Stokes shift for imaging of drug-induced liver injury

Drug-induced liver injury (DILI) has become a common liver disease and a major public health problem. Superoxide anion (O2•-) is closely related to DILI, which can be employed as a biomarker of DILI. In this paper, based on a near-infrared fluorescent dye with quinolinium-xanthene structure and a large Stokes shift, a superoxide anion activatable near-infrared fluorescent probe (QL-3F) was designed and synthesized for imaging of drug-induced liver injury. QL-3F displayed a high sensitivity and an excellent selectivity to O2•-, and also the response mechanism of QL-3F to O2•- was verified by calculation of density functional theory (DFT). Moreover, QL-3F has been successfully applied to image endogenous O2•- in RAW264.7 cells and in HepG2 cells with drug-induced hepatotoxicity. More importantly, QL-3F has been used in monitoring O2•- in DILI mice with satisfactory results. The above results indicated that QL-3F is a useful tool to detect O2•- and diagnose drug-induced liver injury.