Investigation of disaccharide recognition by molecularly imprinted polymers.
The selectivity of carbohydrate-imprinted polymers for several disaccharides, namely cellobiose, maltose, lactose and gentiobiose, is investigated. An ternary ligand-Cu(II)-carbohydrate complex was formed in alkaline solution and captured afterwards in the polymer. The accessibility of the polymer matrix for disaccharides was investigated by HPLC analysis, refractometry and 1H NMR spectroscopy applying excess of the original template during rebinding experiments under saturation conditions in unbuffered, aqueous solution at neutral pH and 20 degrees C. The selective discrimination of the alpha- and beta-glycosidic linkage of cellobiose and maltose is demonstrated. It is further shown, that the disaccharide-imprinted polymers slightly distinguish between the 1,4-beta- and the 1,6-beta-glycosidic linkage of cellobiose and gentiobiose, while cellobiose and lactose are not selectively recognized. Due to the weak apparent binding constant of the functional Cu(II) monomers with the targeted disaccharides at physiological pH, the recognition process is dominated by the shape of the created imprinted cavity under the applied conditions.