Ratiometric Detection of H2S 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 H2S level in the liver, resulting in liver injury. Therefore, tracking the changes of H2S 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 H2S detection in drug-induced liver injury (DILI). Accordingly, here we developed a H2S-activated ratiometric PA probe, namely BDP-H2S, based Aza-BODIPY dye for detecting the H2S upregulation of metformin-induced liver injury. Due to the intramolecular charge transfer (ICT) effect, BDP-H2S exhibited a strong PA signal at 770 nm. Following the response to H2S, its ICT effect was recovered which showed a decrement of PA770 and an enhancement of PA840. The ratiometric PA signal (PA840/PA770) showed excellent H2S 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 H2S in cells and metformin-induced liver injury in mice. Overall, the designed probe emerges as a powerful tool for noninvasive and accurate imaging of H2S level and tracking its distribution and variation in liver in-real time.