Matrix effects on the selectivity of a cholesterol-imprinted polymer

The effect of cross-linkers ethyleneglycol dimethacrylate (EGDM) and divinylbenzene (DVB) on the recognition properties of cholesterol-imprinted polymers, prepared by the sacrificial spacer method, was investigated. As reported previously EGDM-based polymers selectively bound cholesterol in preference to cholest-5-ene-3-one. The addition of up to 30% DVB led to an increase in the binding capacity with very little trade-off in selectivity. However polymers prepared with pure DVB, or DVB/styrene showed complete reversal of selectivity, in some cases binding cholest-5-ene-3-one to the exclusion of cholesterol from a solution containing both ligands. An explanation based on template conformation has been proposed to account for these observations.