Novel Building Blocks for Molecular Imprinting: Pyridine-Based Binding Monomers and Bio-Renewable Cross-Linkers

Molecular imprinting refers to the creation of synthetic materials with built-in memory for a selected target (atom, ion, molecule, complex or a molecular, ionic or macromolecular assembly, including micro-organisms) used as a template to direct the synthesis of the material, a Molecularly Imprinted Polymer (MIP). Here we would like to report on the development of Molecularly Imprinted Polymers (MIPs) for the recognition of molecules of biological/pharmaceutical interest such as biotin and barbiturates using a series of pyridine-based binding monomers which contain hydrogen bonding arrays complementary to their particular targets. MIPs are already widely used for the creation of artificial receptors that will be less expensive, more stable and far more easily reusable compared to their natural counterparts. However there remains plenty of room for improvement in the affinity and selectivity exhibited by MIPs. The common use of commercially available monomers, such as methacrylic acid, is a limitation in the imprinting process. The design of new functional monomers for stoichiometric non-covalent molecular imprinting can enhance the selectivity and specificity of the MIP towards a specific target by decreasing the level of non-specific binding in the polymer, which is generally caused by the use of an excess of functional monomer in the prepolymerisation mixture. Bio-renewable cross-linkers were also synthesised from isomannide, isosorbide and 2,5-bis(hydroxymethyl)furan as a greener and bio-sustainable alternative to ethylene glycol dimethacrylate (EGDMA) in the Molecular Imprinting technology. Herein we will report on the preparation of novel MIPs selective towards uridine prepared using BAAPy as the functional monomer, 2′,3′,5′-tri-O-acetyluridine (TAU) as the dummy template and three acrylate- and methacrylate-based biosustainable crosslinking monomers prepared by esterification of isosorbide (1,4:3,6 dianhydrosorbitol), isomannide (1,4:3,6-dianhydromannitol) and 2,5- bis(hydroxymethyl)furan. The selectivity, specificity and capacity of the reported polymers towards their imprinted templates and similar analytes were evaluated through chromatography and rebinding studies.