Ferrocene-chalcone-based probe for the fluorescence and electrochemical dual-mode detection of carboxylesterase

Carboxylesterases (CEs) are widely distributed in the body and catalyze the hydrolysis of endogenous and exogenous substrates. They play important roles in drug metabolism, and abnormal levels often result in numerous diseases such as cancers. Therefore, it is important to establish a highly selective and sensitive probe for the real-time sensing of CEs activity. Herein, we synthesized a novel fluorescence-electrochemical multichannel probe 1 containing a ferrocene unit, which not only serves as part of the structure of probe 1 but also provides electrochemical signals. The probe exhibited high selectivity to CEs with a "Turn-On" fluorescence response and was applied for imaging in complicated biological samples including Staphylococcus aureus, living cells, and zebrafish. Furthermore, the hydrolysis of the acetoxy group of probe 1 by CEs decreased the electrochemical signal. All these results suggest that probe 1 can act as a multi-modal probe for real-time tracking of the activity CEs in complex biological environments.