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

As one type of reactive oxygen species (ROS), hydrogen peroxide (H(2)O(2)) 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 H(2)O(2) by fluorescence intensity was evaluated. In the design, the arylboronate ester group was acted as a reaction site for H(2)O(2). Upon reaction with H(2)O(2) 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 H(2)O(2) was acquired. Due to the D–A structure formation between N,N′-dimethylaminobenzene and the –CN group and the linkage by thiophene and C[double bond, length as m-dash]C 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 H(2)O(2) 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 H(2)O(2) and its level fluctuation in living cells, which provided a powerful tool for evaluation of cellular oxidative stress and understanding the pathophysiological process of H(2)O(2)-related diseases.