Artificial receptors for the extraction of nucleoside metabolite 7-methylguanosine from aqueous media made by molecular imprinting

• Molecularly imprinted polymers for pre-concentration and extraction of nucleoside derivative cancer biomarkers were prepared.
• A template analogue strategy was employed to overcome nucleoside solubility limitations.
• Best performing materials exhibited selectivity for methylated nucleoside derivatives with imprinting factors up to 6.1.
• Clean extracts and selective recoveries for 7-methylguanosine of up to 90% from artificial urine samples were achieved.

A series of imprinted polymers targeting nucleoside metabolites, prepared using a template analogue approach, are presented. These were prepared following selection of the optimum functional monomer by solution association studies using 1H NMR titrations whereby methacrylic acid was shown to be the strongest receptor with and affinity constant of 621 ± 51 L mol−1vs. 110 ± 16 L mol−1 for acrylamide. The best performing polymers were prepared using methanol as porogenic co-solvent and although average binding site affinities were marginally reduced, 2.3 × 104 L mol−1vs. 2.7 × 104 L mol−1 measured for a polymer prepared in acetonitrile, these polymers contained the highest number of binding sites, 5.27 μmol g−1vs. 1.64 μmol g−1, while they also exhibited enhanced selectivity for methylated guanosine derivatives. When applied as sorbents in the extraction of nucleoside derivative cancer biomarkers from synthetic urine samples, significant sample clean-up and recoveries of up to 90% for 7-methylguanosine were achieved.