Ratiometric Sensing of Hydrogen Peroxide Utilizing Conformational Change in Fluorescent Boronic Acid Polymers

Abstract

We demonstrate that the copolymers containing boronic acid and pyrene units can be utilized for the fluorometric sensing of hydrogen peroxide (H2O2) in aqueous solutions. The copolymer exists in a relatively extended conformation in the absence of H2O2, whereas the polymer chain is contracted by the reaction of boronic acid moieties with H2O2 to form phenol groups. This conformational change induces aggregation of the originally isolated pyrene groups. As a result, relative intensity of excimer emission with respect to monomer emission increases with H2O2 concentration. Accordingly, the present methodology enables us to measure H2O2 by means of ratiometric fluorescence change in the range of 0–30 μM.

WITHDRAWN: Dual targeting of mitochondrial Lon peptidase 1 and chymotrypsin-like protease by small molecule BT317, as potential therapeutics in malignant astrocytomas

“…The boronic acid and potassium salts of trifluoroborate and acid isosteres are known to increase cell permeability and reduce toxicity 42 . Furthermore, boronic acid and ester-based prodrugs were used as templates for ring C because boronic acid is selective for H 2 O 2 33 .…”

“…Previous development of proteasome inhibitors for the treatment of GBM was limited by either poor BBB penetrance (i.e., BTZ) 33 or by the presence of the central nervous system (i.e., MRZ= marizomib, confusion, ataxia) 50 or peripheral nervous system (BTZ, peripheral neuropathy) 51 toxicity. The development of these toxicities is directly related to the level of proteasome inhibition in the blood and in the normal brain 52 .…”

“…Recent work in multiple myeloma has demonstrated the strong synergy with LonP1 and CT-L proteasome inhibition 29 , using specific inhibitors previously shown to have no cross activity, and to target only LonP1, Bardoxolone methyl (CDDO-ME) 30,31 , and the CT-L proteasome activity, carfilzomib (CFZ) 32 . Bortezomib (BTZ) exhibits dual LonP1 and CT-L inhibition and possesses a boronic acid group that can transform into a boronate ester when exposed to reactive oxygen species (ROS) 33 ; however, the major limitation is its poor blood-brain barrier (BBB) permeability 34 . In the subcutaneous U-87 MG and U251 MG glioma models, BTZ was found to sensitize the glioma tumors to TMZ by suppressing FOXM1-mediated treatment resistance 35 .…”

Perylene-Based Smart Fluoroprobe with Dual Function: Ratiometric Response toward Hazardous Organic Peroxides and Pure White Light Generation via Self-Assembly

“…Encouraged by the abovementioned findings, in this work, we have designed and synthesized a fluorescent probe containing boronate ester conjugated with perylene (dibutyl perylene-3,4-dicarboxylate) with improved solubility, , abbreviated as PBE . The boronate group in our designed fluorescent probe PBE was chosen to functionalize at the peri position of the perylene core because of its highly selective reaction toward reactive oxygen/nitrogen species. − The fluorescent probe PBE shows a very fast response toward hazardous peroxide present in old ethereal solvents (like THF, 1,4-dioxane, and diethyl ether) via a visible color change from green to pale yellow. The detection was monitored using UV–vis absorption and fluorescence spectroscopy, which show a ratiometric response toward hazardous OPs.…”