Rational design of a selective and sensitive “turn-on” fluorescent probe for monitoring and imaging hydrogen peroxide in living cells

Abstract

As one type of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) plays a key role in regulating a variety of cellular functions. Herein, a fluorescent probe N-Py-BO was well designed and synthesized and its ability for detecting H₂O₂ by fluorescence intensity was evaluated. In the design, the arylboronate ester group was acted as a reaction site for H₂O₂. Upon reaction with H₂O₂ under physiological conditions, the boronate moiety in the probe was oxidized, followed by detachment from the probe and as a result, a “turn-on” fluorescence response for H₂O₂ was acquired. Due to the D–A structure formation between N,N′-dimethylaminobenzene and the –CN group and the linkage by thiophene and CC bonds to increase the conjugate length, this probe showed a remarkable red shift of emission wavelength (650 nm) as well as a large Stokes shift (214 nm). An excellent linear relation with concentrations of H₂O₂ ranging from 2.0 to 200 μM and a good selectivity over other biological species were obtained. Importantly, taking advantage of the low toxicity and good biocompatibility, the developed probe was successfully applied to monitoring and imaging H₂O₂ and its level fluctuation in living cells, which provided a powerful tool for evaluation of cellular oxidative stress and understanding the pathophysiological process of H₂O₂-related diseases.