Acetylated Trifluoromethyl Diboronic Acid Anthracene with a Large Stokes Shift and Long Excitation Wavelength as a Glucose-Selective Probe

Abstract

Continuous control of blood glucose levels is important for the effective treatment of diabetes. The short-term use of enzymatic continuous monitoring systems involves expensive maintenance and is inconvenient, which limits their widespread use by diabetes patients. The fluorescent diboronic anthracene-embedded system has demonstrated in vivo continuous glucose monitoring for 12 times longer than enzymatic systems by protecting the dye from reactive oxygen species. However, its small Stokes shift and low excitation and emission wavelength should be heavily considered for easy fabrication. We successfully synthesized a derivative of bis-phenyl boronate with a large Stokes shift and long excitation wavelength by adding an acetyl moiety to the anthracene ring. This resulted in a ~90-nm Stokes shift and 15-nm and 80-nm redshifts of the excitation and emission wavelengths, respectively. The fluorescence of the synthesized probe increased proportionally with the glucose concentration because the formation of the boronic acid-glucose complex prevented photoinduced electron transfer. The association constant and quantum yield for acetyl-substituted diboronic anthracene with glucose was 20% and 13% higher than that of the analog, respectively. While keeping resistance to the oxidation by reactive oxygen species, the improved optical properties and glucose-detecting performances of the newly synthesized dye will allow better pairing of the source and detecting unit for in vivo continuous glucose monitoring, leading to easy fabrication and then contributing more to utilization by diabetes patients.