An activated photoacoustic probe for visualization of CO during drug-induced liver injury and repair

Carbon monoxide (CO) is recognized as an essential gasotransmitter molecule due to its reported hypotensive, anti-inflammatory, and cytoprotective properties. Effective monitoring of the CO fluctuations in biology remains challenging during Drug-Induced Liver Injury (DILI) and Repair processes. Until now, there have been few available tools which can measure quantitatively the changes in CO concentration in organisms. The photoacoustic (PA) imaging has been born as a biomedical imaging technology due to its characteristics of deep tissue penetration and non-invasiveness. Therefore, it is particularly crucial to develop an ideal PA probe which allows in situ visualization of CO during Drug-Induced Liver Injury and Repair. Here, we developed a CO-activated PA imaging probe (RP-CO) for early diagnosis of drug-induced liver injury (DILI) and repair. The probe exhibited prominent PA signal turn-on after being selectively activated by CO during DILI and liver recovery. Therefore, this probe successfully located the focus of drug-induced liver injury in vivo and realized the visualization of CO during liver recovery. This developed probe not only provides broad application prospects in the early diagnosis of DILI and the monitoring of liver recovery, but also potentially contribute to exploring more CO-mediated biological processes.