Indocyanine Green-Labeled Antibody-NOTCH2 as a New Fluorescent Molecular Imaging Probe for Gastric Cancer

Gastric cancer is a malignant tumor that seriously threatens human health. Its high mortality is mainly due to delayed diagnosis, which makes early detection important for improving patient prognosis. Near-infrared (NIR) fluorescence imaging, with its high signal-to-noise ratio and good sensitivity, has been widely applied in biomedical research and clinical diagnosis. NOTCH2 is often overexpressed in gastric cancer and may serve as a useful target for diagnosis and treatment. In this study, we constructed a NOTCH2-targeted single-chain variable fragment (scFv) conjugated with indocyanine green (ICG) and evaluated its application in gastric cancer imaging in vitro and in vivo. The ICG-scFv probe showed similar photophysical properties to free ICG and was specifically taken up by MKN45 gastric cancer cells. In NIR imaging, ICG-scFv selectively accumulated in tumor tissue, achieved tumor-specific imaging, and maintained fluorescence signals for a longer time, which was further confirmed by colocalization analysis. These results indicate that the targeted fluorescent probe ICG-scFv may have potential value in the diagnosis and treatment of gastric cancer.