Molecular imprinting is a process that allows for the synthesis of artificial receptors for a given target molecule based on synthetic polymers. The target molecule acts as a template around which interacting and cross-linking monomers are arranged and co-polymerized to form a cast-like shell. In essence, a molecular memory is imprinted in the polymer, which is now capable of selectively binding the target. Molecularly imprinted polymers (MIPs) thus possess the most important feature of biological antibodies - specific molecular recognition. They can thus be used in applications where selective binding events are of importance, such as immunoassays, affinity separation, biosensors, and directed synthesis and catalysis. Since its beginnings in the 1970s, the technique of molecular imprinting has greatly diversified during the last decade both from a materials point of view and from an application point of view. Still, there is much room for further improvement. The key challenges, in particular the binding site homogeneity and water compatibility of MIPs, and the possibility of synthesizing MIPs specific for proteins, are actively addressed by research groups over the World. Other important points are the conception of composite materials based on MIPs, in order to include additional interesting properties into the material, and the synthesis of very small and quasi-soluble MIPs, close in size to proteins.

Chemical nanosensors with a submicrometer core–shell composite design, based on a polymer core, a molecularly imprinted polymer (MIP) shell for specific analyte recognition, and an interlayer of gold nanoparticles for signal amplification, are described. SERS measurements on single nanosensors yield detection limits of 10−7 M for the β‐blocker propranolol, several orders of magnitude lower than on plain MIP spheres.

Molecularly imprinted polymers (MIPs) are tailor-made biomimetic receptors that are obtained by polymerization in the presence of molecular templates. They contain binding sites for target molecules with affinities and specificities on a par with those of natural receptors such as antibodies, hormone receptors, or enzymes. A great majority of the literature in the field describes materials based on polymers obtained by free radical polymerization. In order to solve general problems associated with MIPs, in particular their heterogeneity in terms of inner morphology and distribution of binding site affinities, it has been suggested to use modern methods of controlled/living radical polymerization for their synthesis. This also facilitates their generation in the form of nanomaterials, nanocomposites, and thin films, a strong recent trend in the field. The present paper reviews recent advances in the molecular imprinting area, with special emphasis on the use of controlled polymerization methods, their benefits, and current limitations.