Highly sensitive benzothiazole-based chemosensors for detection and bioimaging of peroxynitrite in living cells.

It is well accepted that peroxynitrite (ONOO) plays a crucial role in various physiological and pathological processes. Thus, the detection and imaging of ONOO and with high selectivity and sensitivity is of great significance. Here we report two simple benzothiazole-based fluorescent chemosensors, BS1 and BS2. Under physiological pH, both probes could quickly sense ONOO with a remarkable "turn-on" fluorescence signal at 430 nm. The limit of detection (LOD) of BS1 and BS2 toward ONOO was 12.8 nM and 25.2 nM, respectively, much lower than the reported values. Experimental results indicated that BS1 with a diphenyl phosphonate unit presented higher selectivity for ONOO than BS2. Furthermore, based on the advantages of lower cytotoxicity and pH-stabilities of BS1, probe BS1 was successfully employed to detect and image ONOO in HepG2 cells. More importantly, we used BS1 to successfully showcase drug-induced hepatotoxicity imaging ONOO upregulated by acetaminophen (APAP), and also evaluated the remediation effect of GSH. All the results illustrated that the fluorescent probe BS1 has great potential for the detection of ONOO and to further uncover the roles of ONOO during the drug-induced liver injury (DILI) process.