Molecularly imprinted hydrogels for application in aqueous environment

Molecularly imprinted thermoresponsive hydrogels for dopamine recognition were synthesized using N -isopropylacrylamide as the temperature-sensitive element, methacrylic acid or itaconic acid as functional monomer and N , N’ -methylenebisacrylamide or ethylene glycol dimethacrylate as crosslinking agent. The stoichiometry of the template–functional monomer prepolymerization complexes was determined by 1 H NMR experiments according to the Job method of continuous variation as well as signal line width analysis. It was found that dopamine hydrochloride forms complexes with methacrylic acid and itaconic acid with 1:3 and 2:3 template to functional monomer stoichiometry, respectively. Hydrogels composed of itaconic acid and with appropriate template content revealed the highest efficiency of imprinting process and relatively high selectivity of dopamine hydrochloride rebinding in water near the phase transition temperature.