Borinic Acids as New Fast-Responsive Triggers for Hydrogen Peroxide Detection.

Abstract

Detection of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), which is responsible for numerous damages when overproduced, is crucial for a better understanding of H<sub>2</sub>O<sub>2</sub>-mediated signalling in physiological and pathological processes. For this purpose, various“<i>off-on</i>” small fluorescent probes relying on a boronate trigger have been developed. However, they suffer from low kinetics and do not allow forH<sub>2</sub>O<sub>2</sub>-detection<sub></sub>with a short response time. Therefore, more reactive sensors are still awaited. To address this issue, we have successfully developed the first generation of borinic-based fluorescent probes containing a coumarin-scaffold. We determined the <i>in vitro</i>kinetic constants of the probe toward H<sub>2</sub>O<sub>2</sub>-promotedoxidation. We measured 1.9x10<sup>4</sup>m<sup>-1</sup>.s<sup>-1</sup>as a second order rate constant, which is 10 000 faster than its boronic counterpart (1.8 m<sup>-1</sup>.s<sup>-1</sup>). This remarkable reactivity was also effective in a cellular context, rendering the borinic trigger an advantageous new tool for H<sub>2</sub>O<sub>2</sub>detection.

Quantitative Factors Introduced in the Feasibility Analysis of Reactive Oxygen Species (ROS)‐Sensitive Triggers

“…As already discussed in Section 3.1, the choice of time point in sampling can skew the "selectivity" in different directions because of the differing kinetics of the boronate reaction with various ROS. Incidentally, there have been efforts to improve the oxidation kinetics with H 2 O 2 by using a borinic acid derivative [120] with a 10,000-fold increase in reaction rate (to k = 1.9×10 4 M À 1 s À 1 ) with H 2 O 2 in comparison to the boronic acid derivative (k = 1.8 M À 1 s À 1 ). However, the reactivity towards two important ROS, ONOO À and HOCl, were not examined in this study.…”