Molecularly Imprinted Overoxidized Polypyrrole Colloids: Promising Materials for Molecular Recognition

This article reviews a novel approach to molecular imprinting technology developed by the authors. Preparation, characterization, and performance of the molecularly imprinted overoxidized polypyrrole colloids is discussed to discriminate amino acid enantiomers and structural isomers of naphthalene compounds by using electrochemical and spectroscopic techniques. An overoxidized colloid, which was prepared with L-lactate as a dopant, shows a higher affinity for L-alanine than for D-alanine, and an uptake ratio (L/D) of as high as 11 was observed under optimum conditions. Furthermore, an overoxidized colloid with a cavity created by 1-naphthalenesulfonate (1-NS) showed a higher uptake for 1-NS than 2-NS. Thus, the shape-complementary cavity created at the colloid surface can precisely recognize the difference in the spatial configuration of enantiomers and structural isomers.