Molecularly imprinted polymers (MIPs) are synthetic antibody mimics ('plastic antibodies') that specifically recognize molecular targets. They are highly cross-linked polymers that are synthesized through the polymerization of monomers bearing suitable functional groups, in the presence of the target molecule acting as a molecular template. This templating induces three-dimensional binding sites in the polymer that are complementary to the template in terms of size, shape and chemical functionality. Thus, the plastic antibody can recognize and bind its target with an affinity and selectivity similar to a biological antibody.
We present here the general principle of molecular imprinting, their optimization, and the synthesis of MIPs using new approaches based on controlled/living radical polymerization and localized photopolymerization. MIPs show specific binding of their targets, small organic molecules (herbicides, antibiotics, mycotoxins...) or proteins, with a nanomolar affinity and a good selectivity. The potential use of these functional nanomaterials in sample preparation, immunoassays and biosensors will be discussed, with special emphasis on food analysis.