A Small‐Molecule NIR‐II Probe for the Diagnosis of Hemorrhagic Diseases

Abstract

Numerous hemorrhagic disorders, particularly those presenting deep hemorrhage, pose diagnostic challenges, often leading to delayed treatment and severe outcomes. Near‐infrared (NIR)‐II fluorescence imaging offers advantages such as deep tissue penetration, real‐time visualization, and a high signal‐to‐background ratio, making it highly suitable for diagnosing hemorrhagic diseases. In this study, an NIR‐II fluorescent probe LJ‐2P carrying carboxylic and phosphoric acid groups is successfully applied for imaging hemorrhagic diseases. LJ‐2P demonstrates a strong affinity for fibrinogen and fibrin clots both computationally and experimentally, thus exhibiting increased brightness upon coagulation. As compared to Indocyanine Green, LJ‐2P provides a longer imaging window, higher imaging specificity, and signal‐to‐background ratio, as well as superior photobleaching resistance in three disease models: gastric, pulmonary, and cerebral hemorrhages. These results reveal that LJ‐2P demonstrates enhanced imaging capabilities, enabling precise identification of hemorrhagic sites.