Photoacoustic Probe for Rapidly Recognizing Superoxide Anion Affording Visualized Tracing of Ferroptosis-Mediated Acute Liver Injury

As an emerging form of regulated cell death, ferroptosis has been identified as a key contributor to the pathogenesis of several diseases. Superoxide anion (O2•-), a key reactive oxygen species, is closely associated with ferroptosis-mediated acute liver injury (ALI). The development of in situ, real-time imaging tools capable of visualizing O2•- will benefit the early diagnosis and therapeutic intervention of ferroptosis-mediated ALI. In this work, we designed and synthesized a photoacoustic (PA) probe, Rho-DOH, based on a rhodamine scaffold, for the specific detection of O2•-. Rho-DOH exhibits a highly sensitive, selective, and fast PA response toward O2•-, characterized by a large bathochromic shift of 125 nm and an activation fold of up to 29-fold. Cellular experiments demonstrate that Rho-DOH enables high-contrast PA imaging of endogenous O2•- in cells. Moreover, Rho-DOH was successfully applied to detect the ferroptosis-mediated ALI and to evaluate therapeutic responses through its O2•--responsive PA imaging signal. These findings position Rho-DOH as a promising molecular imaging tool, offering robust support for the accurate diagnosis and treatment of ferroptosis-associated liver injury.