Design and synthesis of photoacoustic probe for in situ imaging of hydrogen polysulfides in organs in vivo

Hydrogen polysulfide (H 2 S n ), the oxidation product of H 2 S, plays a critical role in driving the signal regulation of ion channels and tumor suppressors, and the homeostatic imbalance of H 2 S n is closely related to various diseases. However, the fluorescence imaging probe for the currently developed H 2 S n cannot realize in situ real-time monitoring of H 2 S n in living organs in vivo because of limited imaging depth . This study reports on the first rational design, synthesis, and evaluation of an H 2 S n -activated photoacoustic (PA) probe (AP-S n ), which enables in situ visual tracking of changes in H 2 S n levels in living organs in mice via H 2 S n -activated PA imaging. After an AP-S n solution was administered to the mouse via tail-vein injection, AP-S n probe responses to H 2 S n in the liver area allowed quick imaging of H 2 S n in the near-infrared window. Changes in H 2 S n levels in the liver attributed to lipopolysaccharides (LPS)-induced overexpression of CSE mRNA were used to monitor the pathological progression of drug-induced acute liver injury (ALI) in inflammatory mice. ALI can be dynamically evaluated in vivo at very high resolutions owing to enhanced depths and low scattering of tissues in the PA image.