A Ratiometric Photoacoustic Probe with a Reversible Response to Hydrogen Sulfide and Hydroxyl Radicals for Dynamic Imaging of Liver Inflammation.

Reversible imaging probes that allow for the dynamic visualization of the redox cycle between hydroxyl radical (⋅OH) and hydrogen sulfide (H2S) are vital to probe the redox imbalance‐involved pathological process in vivo. Herein, we report a reversible ratiometric photoacoustic (PA) imaging nanoprobe (1‐PAIN) for the real‐time imaging of ⋅OH/H2S redox cycle in vivo. 1‐PAIN displays a low PA ratio between 690 and 825 nm (PA690/PA825), which significantly increases by ≈5‐fold upon oxidation by ⋅OH, and is switched back to the initially low PA690/PA825 value upon reduction by H2S. 1‐PAIN could dynamically report on the hepatic ⋅OH production in mice during the lipopolysaccharide (LPS)‐induced liver inflammation process, and visualize hepatic H2S generation during the N‐acetyl cysteine (NAC)‐induced anti‐inflammation process. 1‐PAIN can act as a useful tool to probe the redox state in living biology, beneficial for the study of redox imbalance‐related diseases. [ABSTRACT FROM AUTHOR]