A Self‐Assembled Sensor for Carbohydrates on the Surface of Cyclodextrin Vesicles

Abstract

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 ≈4×10 m ), 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 for d-fructose and 5-400 m 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.

The challenges of glycan recognition with natural and artificial receptors

“…112 Vinylphenylboronic acids can be grafted onto suitably modified nanoparticles, 113 while phenylboronic acid-adamantane conjugates have been reported to form self-assembled monolayers on the surface of cyclodextrin vesicles in aqueous solution. 114 These vesicles presented multiple boronic acid receptors on their surface, which were found to bind monosaccharides with binding constants in the range of 100-3000 M À1 . Moreover, a glucose selective sensor was obtained by the formation of a self-assembled monolayer of bis-boronic acids on gold surfaces.…”

Cyclodextrin-based superparamagnetic host vesicles as ultrasensitive nanobiocarriers for electrosensing

“…19 Vesicles have demonstrated some promising results in the field of electrosensing owing to their straightforward biofunctionalization for selective interactions (i.e., by supramolecular chemistry). [19][20][21][22] Although this research is still in an early stage, vesicles loaded with magnetic nanoparticles would serve as unconventional carriers for analyte preconcentration on a magneto-electrode surface, increasing the surface area and, therefore, amplifying the electroanalytical signal to improve sensitivity and decrease detection limits. Since a major limitation for the use of common magnetic beads is their lack of dispersibility in aqueous media, functionalization with cyclodextrins allows for a series of benefits, including water solubility, biocompatibility and the possibility to immobilize biomolecules on the nanoparticles surface by the formation of host-guest inclusion complexes.…”

A New Colorimetric Platform for Protein Detection Based on Recognition‐Induced Cascade of Polymeric Nanoparticles Disassembly

“…Cyclodextrin (CD) as water‐soluble oligosaccharide with certain cavities exhibits higher affinities with organoboronic acids than ARS . Herein, three popular CDs including α‐CD, β‐CD, and γ‐CD were thought to investigate the signal readout of detection.…”