New configurations and applications of molecularly imprinted polymers

Molecularly imprinted polymers (MIPs) are applicable in a variety of differ ent configurations. For example, bulk polymers imprinted with p-lactam anti biotics are presented to be used as stationary phases for the chromatograph ic separation of p-lactam antibiotics with both aqueous and organic mobile phases. However, in some analytical applications, monosized spherical beads are preferred over the currently used ground bulk polymers. A precipitatio n polymerization technique allows preparation of monosized spherical imprin ted beads with diameters down to 200 nm having excellent recognition proper ties for different target molecules. Nevertheless, with current imprinting protocols a substantial amount of template has to be used to prepare the po lymer. This can be problematic if the template is poorly soluble, expensive or difficult to obtain. It is shown that for analytical applications, the functional monomer:template ratio can be drastically increased without jeop ardizing the polymer's recognition properties. Furthermore, a substantial r eduction of the degree of crosslinking is demonstrated, resulting in much m ore flexible polymers that are useful for example the preparation of thin i mprinted films and membranes for sensors. Apart from analysis, MIPs also ar e applicable in chemical or enzymatic synthesis. For example, MIPs using th e product of an enzyme reaction as template are utilized for assisting the synthetic reaction by continuously removing the product from the bulk solut ion by complexation. This results in an equilibrium shift towards product f ormation. (C) 2000 Elsevier Science BN. All rights reserved.