Biomimicry is the general term covering any approach aimed at reproducing artificially essential properties of one or more biological systems. This is done in order to exploit natural mechanisms or materials for direct applications in different technological domains. One of the main application areas of biomimicry is materials science. At the molecular level, molecularly imprinted polymers (MIPs) are an example, mimicking molecular recognition phenomena.
MIPs are synthetic antibody mimics 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 cross-linked polymer network that are complementary to the template in terms of size, shape and chemical functionality. Thus, these so-called 'plastic antibodies' can recognize and bind their targets with an affinity and selectivity similar to biological antibodies.
We present new approaches allowing for the synthesis of MIP by chemically and spatially controlled radical polymerization. This allows for example to obtain protein-size, soluble MIP nanogels with a homogeneous size distribution. They show specific binding of their targets, small organic molecules or proteins, with a nanomolar affinity and a good selectivity. Other examples are organic-inorganic nanocomposites. Since MIPs are compatible with standard micro and nanofabrication techniques, they can also be obtained in any other physical form, and at the same time interfaced with other materials. The use of these functional nanomaterials for affinity separation, biosensing, bioimaging and theranostics, and other applications will be discussed.