Synthesis of molecularly imprinted polymer of βcyclodextrin for the efficient recognition of cholesterol

Abstract

Polymeric receptors for cholesterol were synthesized by crosslinking β-cyclodextrin (β-CyD) with hexamethylene diisocyanate or toluene 2,4-diisocyanate in dimethyl sulfoxide (DMSO) in the presence of cholesterol as the template. Non-imprinted β-CyD polymers were much poorer in the cholesterol adsorption. When β-CyD was cross-linked by epichlorohydrin in aqueous alkaline solutions (even in the presence of cholesterol), the cholesterol adsorbing activity was nil. Use of DMSO as the cross-linking solvent is necessary for the imprinting, since β-CyD molecules form inclusion complexes with cholesterol in this solvent and thus their mutual conformation in the polymer is regulated appropriately for cholesterol binding. The adsorbed cholesterol was completely removed from the polymers by treating the adducts with ethanol, indicating a strong potential for practical applications.