Engineering a water-soluble cyanine-based probe for plasma butyrylcholinesterase detection and liver injury visualization.

A water-soluble NIR probe, Cy5-QI-BChE, was developed for early liver injury assessment. Its dual quaternary ammonium salts enhanced hydrophilicity to preserve BChE activity in plasma. The quinolinium cation enabled a d-PET-based 72-fold fluorescence enhancement prior to saturation and improved ROS stability via steric hindrance. The probe showed a 1.4 U mL-1 LOD for BChE. In an APAP-induced liver injury mouse model, plasma detection and hepatic imaging revealed significantly lower BChE levels in injured mice versus healthy controls, validated by H&E staining. This offers a promising strategy for drug-induced liver injury screening.