Monosaccharide Binding to Synthetic Carbohydrate Receptor Microarrays.
A glycan detection platform, comprised of synthetic carbohydrate receptors (SCRs) immobilized onto polymer brushes, was prepared. , an alkene-containing SCR, was incorporated into grafted-from polymer brushes using hypersurface photolithography, resulting in microarrays of -functionalized polymer brushes, where brush height () and SCR grafting density (Γ) are controlled precisely at each feature in the array. The influence of and Γ on the binding to five fluorescently labeled monosaccharides-glucose (), α-galactose (), α-mannose (), β-glucose (), and β-galactose ()in aqueous buffer was investigated using fluorescence microscopy. These experiments provided 9072 data points, each corresponding to an individual binding experiment, which were used to assess the effects of polymer , Γ, monosaccharide structure, and monosaccharide concentration on binding avidity ( ). We demonstrate that SCR-based microarrays bind monosaccharides selectively as a result of cooperative, supramolecular interactions that occur within the multivalent polymer brushes. , Hill coefficients, 50% inhibition concentrations, and inhibition constants ( ) were calculated for the different monosaccharide binding pairs and were compared with the binding energies calculated using Density Functional Theory. The SCR-functionalized polymer brush microarrays could detect monosaccharides at micromolar concentrations in aqueous buffers, with as low as 5 μM for . The strength of the monosaccharide-SCR interactions is attributed to the cluster-glycoside effects that can occur within the SCR-functionalized polymer brushes. This report represents the first demonstration that SCRs can function as effective glycan recognition elements in microarray formats.