Hybrid Material for Protein Sensing Based on Electrosynthesized MIP on a Mannose Terminated SelfAssembled Monolayer

A novel strategy to prepare a surface confined molecularly imprinted polymer (MIP) film directly on a transducer surface for protein sensing is achieved by combining interaction with a natural binding receptor and binding to a fully synthetic MIP. A thiolated oligoethyleneglycol (OEG)/mannose conjugate is first self-assembled on the transducer surface. Then the carbohydrate binding protein, concanavalin A (ConA), is vectorially immobilized as a submonolayer on the underlying mannose modified surface. Afterwards, an ultrathin polyscopoletin film with the thickness comparable to that of the protein is electrodeposited on the top. This architecture ensures that the target is confined to the film surface. The resulting functional material shows an approximately 20-fold higher affinity than that obtained from the mannose self-assembled monolayer. This result shows a synergism between multivalent binding of the natural sugar ligand and the non-covalent interactions of the target within the MIP cavities. Recognition capability of the film is characterized by a real-time measurement using quartz crystal microbalance. In comparison to the non-imprinted film, the imprinted film reveals 8.6 times higher binding capacity towards ConA. High discrimination towards the target protein's homologues shows size and shape specificity of the imprint.