Development of functional plastibodies

For many years, molecularly imprinted polymers (MIPs) have been described as "plastic antibodies", yet even some modern examples cannot approach the true binding affinity and specificity of monoclonal antibodies. This project sought to include within the imprinted site a short peptide sequence isolated from a phage display library with high affinity and specificity. A system is hypothesised in which synergism between the robust nature of the polymer and the binding affinity and specificity of the peptide may be exploited. Peptide phage display is a technique that can rapidly enrich binding peptides from a combinatorial library of over 109 unique moieties. Initial studies attempted to isolate peptides with high affinity and specificity to propranolol from this library. However, when several methodologies failed to demonstrate any binding effect, a peptide was selected from the literature that had been found to bind the fluorophore Texas Red. The peptide was immobilised to a Merrifield Resin support, its binding properties thoroughly assessed, and a polymerisation protocol was developed using living radical polymerisation. Preliminary studies suggested that when peptide-functionalised resin was washed in ethanol, no binding to Texas Red was evident, whereas once a protective polymer shell was formed, the peptide retained a binding conformation and affinity for Texas Red was slightly increased. This was, however, at the expense of binding capacity, which fell dramatically. Whilst the evidence presented here is by no means complete, it provides proof-of-principle for a functional peptide- molecularly-imprinted polymer. Further work in this area may lead to the development of a truly biomimetic artificial antibody: the plastibody