Research status of NIR-II fluorescent probe in liver cancer imaging

Liver cancer is a type of malignant tumor with extremely high incidence and mortality rates. For a long time, accurately distinguishing the boundary of liver tumors and achieving accurate resection of liver cancer tissue has been one of the urgent needs of clinical treatment of liver cancer. Fluorescent probes have the advantages of non-invasive, high sensitivity, real-time spatial resolution, etc., and have been widely studied in guiding liver cancer surgical navigation, photothermal therapy, and photodynamic therapy. At present, indocyanine green belongs to zone I fluorescence, which is widely used in the clinic. The shortcomings are shallow penetration depth, non-targeting, easy dispersion, and so on. The near-infrared window II (NIR)-II region has many advantages, such as high spatial resolution, deep penetration, low light absorption and scattering of biological substrates, and minimal fluorescence of tissue itself. In this review, we present the latest advances in the study of fluorescent probes for NIR-II liver cancer and discuss the challenges facing the study of fluorescent probes for NIR-II liver cancer.