Ratiometric Detection of Carboxylesterase In Vitro and In Vivo via a BODIPY-Styryl Platform

Abstract

Hepatocellular carcinoma (HCC) is a highly aggressive liver malignancy and the main form of liver cancer. Early diagnosis and treatment of HCC can effectively reduce mortality. Carboxylesterase (CE) is abundantly present in liver tissue, which shows promise as an innovative diagnostic biomarker for HCC. Herein, we designed and synthesized a novel fluorescent probe BDPPh-CES, based on a boron dipyrromethenes (BODIPY)-styryl framework, for the ratiometric detection of CE. Upon interaction with CEs, the probe demonstrates a characteristic fluorescence emission red shift, completing the reaction within 30 min. Notably, BDPPh-CES maintains specificity against acetylcholinesterase (AChE) and various biological species, while exhibiting robust performance across physiological pH conditions. Comprehensive mechanistic investigations, combining high-resolution mass spectrometry (HRMS) analysis, density functional theory (DFT) computational studies, and molecular docking simulations, provided insights into the binding and sensing mechanisms. The high sensitivity and low cytotoxicity facilitated real-time ratiometric imaging of CEs at the cellular level, successfully distinguishing elevated CE expression in Hepa 1–6 hepatic cancer cells over AML 12 normal hepatocytes. Further validation through in vivo experiments confirmed the liver-specific accumulation and efficient CE detection capabilities. This research presents an innovative approach for ratiometric CE monitoring, with potential implications for the early detection and therapeutic management of CE-associated disorders such as HCC.