Functionalized Vesicles Based on Amphiphilic Boronic Acids: A System for Recognizing Biologically Important Polyols

We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-3-boronopyridinium triflates (alkyl = Me, C12H25, C16H33) as sensors for monosaccharides. The nanoaggregate properties were studied by means of DLS, TEM, high-resolution H-1 NMR, and the solvatochromic dyes Reichardt's betaine and Methyl Orange. The vesicles were shown to have 30-200 nm diameters depending on the amphiphile chain length. Diol binding to the vesicles was studied by steady-state fluorescence and UV-vis using Alizarin Red S as a probe in the solution at pH 7.4 in the presence and in the absence of D-glucose and D-fructose. Strong sensing ability of boronic acid functional moieties in the order D-fructose > D-glucose was demonstrated, and apparent binding constants were estimated.