Carbohydrate Recognition in Cross-Linked Sugar-Templated Poly(acrylates)

Abstract

A low reloading capacity is a serious weakness for any recognition material. To raise the overall amount of saccharides bound by templated poly(acrylates) with immobilized copper(II) complexes, I enlarged the number of attractive binding forces inside the matrix by polymerizing cross-linking monomers with various amounts of free hydroxyl groups. The material preparation was conducted in the presence of either aqueous methanol or alkaline water as porogenic solvent. All rebinding experiments were carried out in water at physiological pH. Positive ion ESI mass spectrometry shows only weak copper(II)−saccharide interactions under sugar rebinding conditions. The formation of multiple hydrogen bondings between the polymer backbone and the sugar template are demonstrated to be advantageous for the overall material capacity. Increasing the flexibility of the polymer backbone in a templated polar matrix enhances the overall material capacity for disaccharides (∼80 μmol of sugar per gram polymer) and diminishes the material selectivity only slightly. The polymer selectivity for discrimination of α- and β-glycosidic bonds in the disaccharides maltose and lactose is higher in a polar than in a nonpolar matrix. The polymer preference for the smaller, less polar monosaccharide glucose decreases along with an increasing matrix polarity in favor of the larger, more polar disaccharide lactose.