A Fast Responsive, Highly Selective And Light-up Fluorescent Probe For The Two-photon Imaging of Carboxylesterase In Living Cells

A fast responsive and two photon fluorescent probe (HCyNAc) for carboxylesterase (CaE) has been designed based on the D–π–A structure of hemicyanine and naphthalene derivatives. After enzymatic reaction, HCyNAc enabled light-up fluorescence assay of CaE over other biologically-relevant species and enzymes, including ROS. Two-photon imaging of endogenous CaE was confirmed in HeLa cells using HCyNAc under 800 nm NIR excitation.