Synthesis and characterization of molecularly imprinted microspheres

A novel method for the preparation of molecularly imprinted microspheres ha s been developed. Theophylline, caffeine, and 17 beta -estradiol are,used a s template molecules to demonstrate the generally applicable methodology. I n the presence of a template molecule, cross-linking polymerization startin g from a dilute solution of methacrylic acid and trimethylolpropane trimeth acrylate yields polymer microspheres bearing imprinted binding sites. Radio ligand binding analysis confirms that very high binding specificity is reta ined when the molar ratio of functional monomer:cross-linker is controlled between 1:1 and 2.3:1. Nonspecific binding of molecularly imprinted microsp heres decreases when an increasing amount of template molecule is used for polymer preparation. Compared with previously reported suspension polymeriz ation and seed polymerization, the present method is highly efficient, is g enerally applicable to various template molecules, and gives uniform micros pheres in good yield.