Ultrasensitive fluorescent probe for visual biosensing of esterase activity in living cells and its imaging application

Esterase activity is often used as an index to evaluate the health status of cells and plays an important role in cell metabolism and apoptosis. Herein, we develop two fluorescent probes for visual biosensing of esterase activity and imaging in living cells. In vitro, after the introduction of esterase, enzymolysis destroys the ester bond of the probe, causing the fluorescent color of probe changes from yellow to red, thus realizing the visual strategy for determination of esterase activity, with high sensitivity and selectivity. Especially, probe VA, 2-(4-acetoxystyryl)-3-ethyl-1,1-dimethyl-1H-benzo[e]indol-3-ium, exhibits higher sensitivity with a lower detection limit (up to 7.15 x 10(-6) U/mL). In the cell experiment, the fluorescent probe VA also shows good biocompatibility and high spatial resolution, and is successfully applied to the intracellular fluorescent imaging and biosensing of esterase in living cells. More importantly, the probe VA can judge the unhealthy state of H2O2-induced HeLa cells using dual-fluorescence signals. The results confirm that the fluorescence method is a reliable tool for detecting endogenous esterase in living biological system. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study developed two new fluorescent probes for visual detection of esterase activity in cells and imaging in living cells. The probe VA showed higher sensitivity and lower detection limit. These probes have high biocompatibility and high spatial resolution, providing a reliable method for detecting endogenous esterase.