摘要:

Antibodies are natural receptor molecules that are routinely utilised as analytical reagents in clinical and research laboratories. One of their most common applications is in immunoassays.1The many different assay formats that have been developed to date have in common as an important step the specific recognition and binding of an antigen by an antibody, thereby the antigen fits exactly into the antibody’s binding site, whereas other, even closely related compounds are excluded from the site.Researchers have attempted to replace antibodies with smaller, more stable counterparts, and have also been searching for ways to obtain artificial antibody-like receptors. One technique that is being increasingly adopted for the generation of artificial macromolecular receptors is molecular imprinting of synthetic polymers.2–4One of the milestones in the development of this technology was the demonstration that imprinted polymer particles can be substituted for antibodies in immunoassays.5The first molecularly imprinted sorbent assay (MIA) was based on a competitive radioligand-binding measurement. This format is analogous to solid-phase radioimmunoassay, except that the immobilised antibody is replaced with a molecularly imprinted polymer (MIP).5Other assays developed later have used the same principle.6,7Unfortunately, radioassays involve the handling of radioactive materials and produce radioactive waste, which are undesirable and therefore make the development of assays based on other labels and detection methods attractive. For alternative competitive MIAs one can, in analogy to immunoassays, imagine different approaches. Fluorescent labels8or non-related fluorescent probes9have been suggested, since they were considered the most compatible with MIPs. Enzyme labels, on the other hand, although most common with immunoassays, seemed to be less practical in MIAs for two reasons: First, enzymes often only work in aqueous buffers, whereas the use of many imprinted polymers is restricted to organic solvents. Second, the rather hydrophobic nature and highly cross-linked structure of the polymer limits the access of the large protein molecules to the imprinted binding sites. Thus, the development of a MIP-based ELISA has remained a challenge. However, during the last few years MIPs that perform well in aqueous solvents have been developed,7,10–12and the problem of binding site accessibility might be circumvented by using, instead of large porous MIP particles, imprinted microspheres that have binding sites at or close to their surface.In the present paper we demonstrate the feasibility of developing imprinted polymer-based immuno-type assays using an enzyme-labelled antigen. As a model system we have chosen as the selective binder a MIP specific for the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), which can be used in aqueous buffer,12and the enzyme tobacco peroxidase for colorimetric and chemiluminescence detection.

ISSN:0003-2654    

出版商:RSC    

年代:1999

数据来源: RSC