Rapid-Response and Highly Sensitive Boronate Derivative-Based Fluorescence Probe for Detecting HO in Living Cells.

Intracellular HO monitoring is important and has driven researchers to pursue advancements for the rapid identification of HO, since HO is short-lived in cell lines. An arylboronate derivative has been investigated as a chemospecific fluorescence recognition agent for HO. Triphenylimidazoleoxadiazolephenyl (TPIOP) boronate was contrived as a novel candidate for the rapid and sensitive recognition of HO. The probe was conjugated using the TPIOP functional group acting as an excellent fluorescent enhancer. The TPIOP group stimulated the polarization of C-B bond due to its extended -conjugation, which included heteroatoms, and induced the production of rapid signal because of the highly polar C-B bond along with the corresponding boronate unit. While HO reacts with TPIOP boronate, its nucleophilic addition to the boron generates a charged tetrahedral boronate complex, and then the C-B bond migrates toward one of the electrophilic peroxide oxygen atoms. The resulting boronate ester is then hydrolyzed by water into a phenol, which significantly enhances fluorescence through aggregation-induced emission. The TPIOP boronate probe responded to HO rapidly, within 2 min, and exhibited high sensitivity with a limit of detection of 8 nM and a 1000-fold selectivity in the presence of other reactive oxygen species. Therefore, the developed TPIOP boronate chemodosimeter was successfully utilized to visualize and quantify intracellular HO from human breast cancer (MCF-7) cells, as well as gaseous and aqueous HO from environmental samples using Whatman paper strips coated with TPIOP boronate.