Ratiometric Detection of H 2 S in Liver Injury by Activated Two-Wavelength Photoacoustic Imaging.

Metformin is commonly used for clinical treatment of type-2 diabetes, but long-term or overdose intake of metformin usually causes selective upregulation of H 2 S level in the liver, resulting in liver injury. Therefore, tracking the changes of H 2 S content in the liver would contribute to the prevention and diagnosis of liver injury. However, in the literature, there are few reports on ratiometric PA molecular probes for H 2 S detection in drug-induced liver injury (DILI). Accordingly, here we developed a H 2 S-activated ratiometric PA probe, namely BDP-H 2 S, based Aza-BODIPY dye for detecting the H 2 S upregulation of metformin-induced liver injury. Due to the intramolecular charge transfer (ICT) effect, BDP-H 2 S exhibited a strong PA signal at 770 nm. Following the response to H 2 S, its ICT effect was recovered which showed a decrement of PA 770 and an enhancement of PA 840 . The ratiometric PA signal (PA 840 /PA 770 ) showed excellent H 2 S selectivity response with a low limit of detection (0.59 μM). Bioimaging experiments demonstrated that the probe has been successfully used for ratiometric PA imaging of H 2 S in cells and metformin-induced liver injury in mice. Overall, the designed probe emerges as a powerful tool for noninvasive and accurate imaging of H 2 S level and tracking its distribution and variation in liver in-real time.