Molecular imprinted binding sites, synthesis

More often than not, molecular imprinting in polymers has involved the synthesis of a crosslinked polymeric network around a template molecule [27,28]. Generally an appropriate template molecule, T, is identified or synthesised in order to complex with suitable polymerisable binding sites in a solvent (Fig. 8). A crosslinking comonomer and a free radical initiator are added, and a radical chain polymerisation initiated thermally. 

Fig. 22.2 Schematic procedures for the synthesis of molecularly imprinted catalysts (a) with organic binding sites Right triangle, Filled circle, Filled square) (e.g., NH, NH, OH, and COOH) on the wall of a polymer matrix and (b) using a metal complex coordinating a template ligand...

Shea KJ (1994) Molecular imprinting of synthetic network polymers the synthesis of macro-molecular binding and catalytic site. Trends Polym Sci 2 166... 

Shea, K.J, Molecular imprinting of synthetic network polymers the de-novo synthesis of macromolecular binding and catalytic sites, Trends. Polym. Sci. 1994, 19, 9-14... 

Another example of new sorbents is the molecular imprinted polymers (MIP) from the work of Siemann and co-workers (1996). They synthesized a methacrylic acid-ethylene glycol dimethacrylate copolymer with atrazine as an imprint molecule. Imprint synthesis entails polymerization around an imprint species with monomers that are selected for their ability to form specific and definable interactions with the imprint molecule. The atrazine is chemically removed from the polymer leaving holes or cavities. The cavities are formed in the polymer matrix whose size and shape are complementary to that of the imprint molecule (Siemann et al., 1996). These recognition sites enable the polymer to rebind the imprint species selectively from a mixture of closely related compounds, in many instances with binding affinities approaching those demonstrated by antigen-antibody systems. 

The synthesis of a molecularly imprinted polymer is at first sight a straightforward affair. A template molecule, which can essentially be freely chosen, is mixed together with one or several polymerisable receptor molecules ( functional monomers ) [11-14] (Fig. 1). The latter, so-called binding sites, are selected on the basis of preferably strong and directed interactions with the template molecule to maximise the molecular fidelity of the imprinting process (covalent and non-covalent interactions are possible). This step... 

Shea, K. Molecular imprinting of s)mthetic network polymers. The De Novo synthesis of macromolecular binding and catalytic sites. Trend Polym. Sd. 1994,2, 166 173. 

Molecular imprinting is a method for the synthesis of polymers with predeterminated selectivity for various compounds. This technique uses noncovalent prearrangement of functional monomers in the presence of the print molecules prior to the polymerization for the creation of highly specific binding sites. After polymerization the print molecules are washed out of the macroporous polymer matrix. The result is a polymer with recognition sites due to the shape of the print molecules. The proper arrangement of the functional groups in the polymer have the affinity for the print molecules. This fact leads to the restriction that the structure of the enantiomers, to be separated, must be very similar to these of the print molecules. 

---