Synthesis and characterization of molecularly imprinted polymer films

The solution-phase synthesis was developed for preparing molecularly imprinted polymers (MIPs) against Boc-L-Trp using a binary monomer system. Methacrylic acid (MAA) and 2-vinylpyridine (2-VPy) were used as the two functional monomers with ethylene glycol dimethacrylate (EGDMA) as the crosslinker. Polymers prepared from two monomers showed improved binding strength and recognition capabilities compared to polymers that were prepared using a single monomer. The synergistic effect on binding was most pronounced for polymers prepared from a starting MAA:2-Vpy molar ratio of about 1:5. A correlation was developed based on molecular interaction scales to relate the template-MIP binding strength to MIP composition.; Experimental data demonstrated the successful preparation of ultrathin (<10 nm), surface-confined, molecularly imprinted polymer (MIP) films on model gold substrates using atom transfer radical polymerization (ATRP). 2-Vinylpyridine (2-Vpy) was investigated as the functional monomer and ethylene glycol dimethacrylate (EGDMA) was the crosslinking monomer. Fluorescently-labeled N,N' -didansyl-L-cystine and N,N'-didansyl-L-lysine were used as the template molecules to form the MIPs. Spectroscopic and ellipsometric results are presented that follow film formation and growth rates. Results are also presented from fluorescence experiments used to quantify and compare the adsorption capacities of MIP surface films and non-imprinted (NIP) control films. MIP films exhibited higher binding capacities than the control NIP films at all solution concentrations of N,N'-didansyl-L-cystine and N,N'-didansyl-L-lysine. Selectivity studies showed that the MIPs display some cross-reactivity between these two molecules. A selectivity coefficient of 1.13 was achieved for MIP surfaces prepared against N,N'-didansyl-L-lysine; a value of 1.51 was observed for MIP surfaces prepared against N,N'-didansyl-L-cystine.; Imprinted polymers were grafted successfully onto silica gel via ATRP. Experimental binding kinetics for the MIP-SG (Silica Gel) materials demonstrated improved mass transfer properties than MIP prepared by solution phase synthesis. In addition, the column packed with MIP-SG showed higher column efficiency and better resolution for the enantiomers than that packed with a conventional MIP. When Boc-L-Trp was used as the template molecule, the column packed with the resulting polymer retained the Boc-L-Trp to longer elution time than the Boc-D-Trp. This order of elution was switched when Boc-D-Trp was used as template.