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

Detection of hydrogen peroxide (H₂O₂), which is responsible for numerous damages when overproduced, is crucial for a better understanding of H₂O₂-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 forH₂O₂-detectionwith 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 H₂O₂-promotedoxidation. We measured 1.9x10⁴m^-1.s^-1as a second order rate constant, which is 10 000 faster than its boronic counterpart (1.8 m^-1.s^-1). This remarkable reactivity was also effective in a cellular context, rendering the borinic trigger an advantageous new tool for H₂O₂detection.