General principle of molecular imprinting
The technology of molecular imprinting allows for the preparation of synthetic polymers with specific binding sites for a target molecule. This can be achieved if the target is present during the polymerization process, thus acting as a molecular template. Monomers carrying certain functional groups are arranged around the template through either noncovalent or covalent interactions. Following polymerization with a high degree of cross-linking, the functional groups are held in position by the polymer network. Subsequent removal of the template by solvent extraction or chemical cleavage leaves cavities that are complementary to the template in terms of size, shape and arrangement of functional groups. These highly specific receptor sites are capable of rebinding the target molecule with a high specificity, sometimes comparable to that of antibodies. Molecularly imprinted polymers have therefore been dubbed « antibody mimics ». It has been shown that they can be substituted for biological receptors in certain formats of immunoassays and biosensors. They have also been used as stationary phases for affinity separations, for the screening of combinatorial libraries, and as enzyme mimics in catalytic applications.