Molecularly imprinted polymers characteristics

Molecularly imprinted polymers have come to be recognised as antibody mimics since Mosbach and co-workers demonstrated the use of imprinted polymers for the sorbent assay of drugs [1], Not only in applications, but also in preparation principle, imprinted polymers can be regarded as antibody mimics the synthesis proceeds in a tailor-made fashion and the resultant polymers show specific binding for a given guest molecule. Also, imprinted polymers have many characteristic features as synthetic antibody mimics that contrast with natural antibodies. 

The design of new assays is often limited by the availability of antibodies with the desired characteristics. In conventional immunoassays, antibodies are used, however, other recognition elements, including binding proteins, receptors, molecular imprinted polymers (MIPs), and... 

Reddy, P.S. Kobayashi, T. Fujii, N. Recognition characteristics of dibenzofuran by molecularly imprinted polymers made of common polymers. Eur. Polym. J. 2002, 38, 779-785. 

All these factors must be taken into account when attempting to fabricate monoliths with not only good flow-through characteristics but also optimized pore distributions for a specific application. The novel work by Frechet and Svec in 1992, which optimized the porosity of a methacrylate-based polymer for chromatography application, was a jumping point for many subsequent studies on macroporous monoliths. As discussed in the following sections, their protocol was absolutely influential on the first attempts at combining monoliths with molecularly imprinted polymers. 

Table 18.5 Characteristics and figures of merit for automated solid-phase extraction of riboflavin and determination by HPLC-DAD. The procedure proposed by Oliveira et al. (2010) is based on automatic SPE using a renewable column of commercially available molecularly imprinted polymers selective to riboflavin. The solid-phase extraction procedure was coupled online to the reversed phase chromatographic determination, resorting to a monolithic silica C18 column.

Song, X., J. Li, J. Wang, and L. Chen. 2009. Quercetin molecularly imprinted polymers Preparation, recognition characteristics and properties as sorbent for solid-phase extraction. Talanta 80(2) 694-702. 

Y.W. Tang, Z.F. Huang, T. Yang, X.G. Hu and X.O. Jiang, The characteristic and application of molecularly imprinted polymer Efficient sample preconcentration of antibiotic cefa-thiamidine from human plasma and serum by solid phase extraction. Anal. Lett., 38 (2) 219-226, 2005. 

Thin fQm of molecularly imprinted polymer can be prepared on a SPR chip, and the specific binding activity can be monitored as a change in angle for tight reflected from the chip. However the preparation of molecularly imprinted polymer on the chip requires often a careful control of polymer composition. The most common method involves the free radical polymerization with the use of a photo-initiator, and this process can lead to changes of template structure in the case of proteins their denaturation occurs. Other preparation procedures of molecularly imprinted polymers for SPR are atom transfer radical polymerization and polymer grafting method these methods provide a better control of the film physical characteristics, but require a suitable catalyst for polymerization. 

It should be noted that the presence of cross-links results in the partial or complete loss of control over the size of the polymer molecules, even if the living character of the polymerization can sometimes be preserved. Incidently, one of the characteristics of MIPs is that they are cross-linked polymers. This cross-linking is necessary in order to maintain the conformation of the three-dimensional binding sites obtained through the molecular imprinting process, and thus the ability of the polymer to recognize specifically and selectively its target molecule. Nevertheless, even with cross-linked polymers, the use of CRP methods may be beneficial, as it can, up to a certain point, improve the structure of the polymer matrix. Indeed, all of the above CRP methods have been applied to MIPs. 

Kim K, Kim D (2005) High-performance liquid chromatography separation characteristics of molecular-imprinted poly(methacrylic acid) microparticles prepared by suspension polymerization. J Appl Polym Sci 96(1 ) 200—212... 

Besides the polymer structure, the type of the binding site interaction is the most important characteristic feature of the molecular imprinting procedure. This interaction should optimally show the following properties during the different steps of their use in the imprinting procedure ... 

Burow, M. Minoura, N. Molecular imprinting synthesis of polymer particles with antibody like binding characteristics for glucose oxidase. Biochem. Biophys. Res. Commun. 

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