Sugar Binding Polymers Showing High Anomeric and Epimeric Discrimination Obtained by Noncovalent Molecular Imprinting

Noncovalent molecular imprinting of sugar compounds in ethylene glycol dimethacrylate-methacrylic acid copolymers yielded materials containing highly selective sugar binding sites. Investigation of a range of polymers demonstrated that the resulting polymer imprints have a high degree of both anomeric and epimeric selectivity favoring the original print molecule. In HPLC assays, a polymer imprinted using p-nitrophenyl-α-D-galactoside could separate the α and β anomers of the same compound with near baseline resolution. A polymer imprinted using p-nitrophenyl-β-D-galactoside showed similar results but with the β anomers retained longer as expected. Anomeric discrimination of closely related sugars was also possible, with the degree of separation depending on the structural resemblance to the print molecule. Similarly, a polymer imprinted with p-nitrophenyl-α-L-fucoside could separate α/β mixtures of p-nitrophenyl-L-fucoside with baseline resolution. Using radioligand displacement assays a polymer imprinted using octyl-α-D-glucoside was shown to bind methyl-α-D-glucoside with a 40-fold higher affinity than that for the β-anomer. The epimeric selectivity was even more impressive: methyl-α-D-mannoside and methyl-α-D-galactoside had 130- and 240-fold lower affinity, respectively, than methyl-α-D-glucoside. The results are discussed in relation to possible uses of such polymers in separation and analysis.