Rational Design of a Highly Selective Near‐Infrared Two‐Photon Fluorogenic Probe for Imaging Orthotopic Hepatocellular Carcinoma Chemotherapy

Selective fluorescence imaging of biomarkers in vivo and in situ for evaluating orthotopic hepatocellular carcinoma (HCC) chemotherapy remains a great challenge due to current imaging agents suffering from the potential interferences of other hydrolases. Herein, we observed that carbamate unit showed a high selectivity toward the HCC‐related biomarker carboxylesterase (CE) for evaluation of treatment. A near‐infrared two‐photon fluorescent probe was developed to not only specially image CE activity in vivo and in situ but also target orthotopic liver tumor after systemic administration. The in vivo signals of the probe correlate well with tumor apoptosis, making it possible to evaluate the status of treatment. The probe enables the imaging of CE activity in situ with a high‐resolution three‐dimensional view for the first time. This study may promote advances in optical imaging approaches for precise imaging‐guided diagnosis of HCC in situ and its evaluation of treatment. In this report, we show that a carbamate as recognition unit has an excellent selectivity for a hepatocellular carcinoma chemotherapy (HCC)‐related biomarker (carboxylesterase, CE) without interference from other hydrolases. We developed a near‐infrared two‐photon fluorescent probe with high selectivity and strong fluorescence signals towards CE activity, enabling it to successfully monitor CE activity for evaluating HCC chemotherapy in vivo.