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A Self‐Assembled Sensor for Carbohydrates on the Surface of Cyclodextrin Vesicles
Author(s) -
Himmelein Sabine,
Ravoo Bart Jan
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201603115
Subject(s) - vesicle , chemistry , boronic acid , liposome , cyclodextrin , supramolecular chemistry , fluorescence , amphiphile , aqueous solution , bilayer , binding constant , monosaccharide , lipid bilayer , organic chemistry , membrane , binding site , biochemistry , molecule , physics , quantum mechanics , copolymer , polymer
A supramolecular carbohydrate sensor was prepared by self‐assembly of unilamellar bilayer vesicles of amphiphilic β‐cyclodextrin with a boronic acid–adamantane conjugate (PBA‐AD), which binds strongly to β‐cyclodextrin through host–guest interactions ( K a ≈4×10 4 m −1 ), so the vesicle surface exhibits multiple boronic acid receptors for carbohydrates. The binding of diols to the functionalized vesicles was tested with alizarin red S (ARS) as a reporter dye by using fluorescence and UV/Vis spectroscopy. Analysis of the competitive binding of monosaccharides revealed pH‐dependent (pH 7.4–10.1) binding constants in the range of 100–3000 m −1 for d ‐fructose and 5–400 m −1 for d ‐glucose. Interestingly, the self‐assembled sensor showed fluorescence intensity enhanced by about fivefold and a binding affinity to the reporter dye increased by about eightfold in comparison to PBA‐AD and ARS without vesicles. This is attributed to increased local concentration of ARS and PBA‐AD on the surface of the vesicles. Detection of d ‐fructose and d ‐glucose was possible in the physiologically relevant range in dilute aqueous solution.