Surface imprinting of cholesterol on submicrometer core-shell emulsion particles

Submicrometer surface-imprinted particles were prepared by a two-stage aque ous emulsion polymerization with a poly(divinylbenzene) shell over a cross- linked poly(styrene) core. The second stage polymerization was performed in the presence of a polymerizable surfactant (pyridinium 12-(4-vinylbenzylox ycarbonyl)dodecanesulfate, PS) and pyridinium 12-(cholesteryloxycarbonyloxy )dodecanesulfate (TS), which acted both as a surfactant and as a template. Removal of the template left hydrophobic cavities on the surface of charged particles or particles bearing benzyl alcohol groups, dependent on the pro tocol adopted. Particles were shown to rebind cholesterol in 60% a-propanol in water, and a poly(ethylene glycol) (PEG) modified with cholesterol at b oth chain ends was capable of flocculating the imprinted particles. No floc culation was seen either when a monocholesteryl PEG was used or when nonimp rinted particles were used.