MOLECULARLY IMPRINTED POLYMERS AS ARTIFICIAL STEROID-RECEPTORS

The polymers selective to six different steroids (testosterone, Delta( 4) -androstene-3, 17-dione, 1,4-androstadiene-3, 17-dione, beta-estrad iol progesterone, testosterone propionate) have been synthesized using molecular imprinting based on noncovalent interactions. Analysis of t he influence of structural features of the steroids under study has sh own that molecules with a relatively rigid structure and the OH group at C-17 position are the most efficient templates for methacrylic acid -containing imprinted polymers. The chromatographic study of the polym ers synthesized has demonstrated a strong dependence of the selectivit y and intensity of interaction with analytes on the composition of sol vents used both as porogen and chromatographic mobile phase. To obtain polymers with highly selective recognition sites and to create the op timal conditions for molecular recognition, all possible interactions (between template and functional monomer, template and solvent, solven t and functional monomer) should be taken into account. The batch rebi nding study of testosterone by the imprinted polymer in acetonitrile h as revealed some heterogeneity of recognition sites and permitted dete rmination of K-ass = 1.05 x 10(4) M-1, Delta G degrees= -5.4 kcal/mol and N=1.2 mu mol/g for high-affinity sites and K-ass = 0.33 x 10(4) M- 1 ,Delta G degrees = -4.8kcal/mol and N = 2.2 mu mol/g for low-affinit y sites. The results obtained show how it is possible to regulate in d ifferent modes the molecular recognition by imprinted polymers as well as to fabricate polymers possessing the necessary properties dependin g on their practical application. (C) 1998 John Wiley & Sons, Ltd.