A Small Molecule Chemiluminophore with near 600 nm Emission for In Vivo Imaging of Myeloperoxidase and Inflammatory Diseases

Chemiluminescence has emerged as a vital tool for bioimaging in vivo. The red shift emission of chemiluminophores is extremely useful for in vivo bioimaging. In this work, the conjugation system of the luminol was extended to achieve a red-shifted emission (591 nm) along with excellent water solubility. The probe (HM-ASPH-PF) has a molecular weight of only 396.42, which contains a benzothiazole and a cyclic phthalhydrazide structure. The probe has been used for in vivo luminescence imaging of neutrophil-mediated acute liver injury, including alcoholic liver injury (ALI) and acute liver failure (ALF) in mice, by exploiting myeloperoxidase (MPO) as a biomarker. The activated neutrophils were specifically imaged by HM-ASPH-PF. HM-ASPH-PF was also successfully applied to monitor the neutrophils in livers in mouse models of ALI and ALF. Consequently, HM-ASPH-PF, as an effective luminescent small molecule that possesses a red-shift emission near 600 nm, has been applied for the detection of MPO in living cells and neutrophil-mediated acute liver injury. This work also demonstrates the applied potential of the luminescent probe for the diagnosis of other neutrophil-associated liver diseases.