Doctor of Philosophy (PhD)
Most of the research in the field of molecular imprinting has been focused on the development of new functional monomers, in order to improve the molecular recognition properties afforded by these materials. The role of the crosslinking monomer has often been overlooked, since it is considered an inert component that only provides a scaffold to support the binding sites. However, the crosslinking monomer represents a high percent (80-90%) of the composition of molecularly imprinted polymers (MIPs), which can have a large influence on the MIPs properties. This research addresses the design, synthesis, and applications of new crosslinking monomers for molecular imprinting. Crosslinking monomers containing different polymerizable groups (methacrylate/methacrylamide, methacrylamide/vinylketone, and methacrylate/vinyl ketone) were synthesized and used to prepare MIPs. Key steps in the synthesis of these monomers involved the use enzymatic methodologies to selectively deprotect methyl esters. To avoid an undesirable intramolecular Michael addition, N-methyl-N-methoxy amides derivatives were used as electrophiles to introduce the vinylketone functionality via nucleophilic addition of a Grignard reagent. Enhancement in molecular recognition properties exhibited by MIPs prepared with crosslinking monomers incorporating the amide functionality was attributed to cooperative interactions within the crosslinking with the template molecule, as well as an improved morphology that arises from the reactivity differential of the polymerizable groups. Incorporation of the binding functionality in a crosslinking format allowed to maximize the degree of crosslinking without imposing restrictions on functional group concentrations. An important breakthrough for the simplification of the molecular imprinting process was achieved by the use of a one single monomer, which incorporates an amide functionality for binding the template molecule and the polymerizable groups to form the polymeric network. The advantage of using this single monomer is that there is not need to optimize the functional/crosslinking monomer ratio. The strategy of using functionalized crosslinking monomers derived from natural amino acids, to provide the functional groups for catalytic activity was investigated using a combinatorial approach for fast screening. Finally, modification of biological matrices using bioimprinting methodologies was explored by imprinting a Class I aldolase antibody with an aldol reaction product in order to improve its catalytic activity in organic solvents.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Sibrian-Vazquez, Martha, "Design, synthesis, and applications of bio-derived crosslinking monomers for molecular imprinting" (2003). LSU Doctoral Dissertations. 2921.
David A. Spivak