Preparation And Evaluation Of The Dual-template And Chiral Dopant-based Molecularly Imprinted Monolith

Multi-template imprinting is one of new fields for molecular imprinting. In present work, a new method based on molecularly imprinted polymers(MIPs) with multiple templates was developed and polymerization parameters on the effect of imprinting was discussed. A double template molecularly imprinted polymers(MIPs) with metal ions as pivot was developed for higher fidelity of imprint. Imprinted monoliths were synthesized using two templates, S-naproxen(S-NAP) and ketoprofen(KET), 4-vinylpyridine as functional monomer, ethylene glycol dimethacrylate as crosslinker, and a number of metal ions as pivot between the template and functional monomer. The effect of polymerization parameters such as the ratio of S-NAP to KET, the ratio of template to monomer and the degree of crosslinking, on the permeability, morphology and affinity of the metal ion mediated MIP monolith were studied. The best affinity was obtained on the MIPs prepared with a molar ratio of SNAP:KET:Co2+:4-VP:EDMA of 0.5:0.5:1:6:24. Greater imprinting effect was found on the Co2+-mediated MIP monolith which were higher than the corresponding single-template MIP monolith and the MIP monolith in the absence of metal ions. The results revealed that the use of cobalt ion as pivot is an effective method for improving the recognition specificity and selectivity of D-MIC. The imprinting effect was not decreased for imprinting two templates at the same time. This is the first time for synthesizing D-MIC with metal ions as pivot, and affinity screening of structurally similar compounds with the template can be achieved on the D-MIC. This study provides a new way for improving the imprinting effect of double template imprinting.In the second work, a new method by adding chiral dopant into liquid crystalbased imprinted system was suggested to improve imprinting effect of MIPs. For the preparation of liquid crystal-based MIPs, amlodipine was used as template, MPDE liquid crystal monomer, ethylene glycol dimethacrylate crosslinker in the presence of a number of chiral dopant. It was found that for the AML-based system, 40% liquid crystal monomer was the lowest amount to afford the imprinting effect derived from chiral dopant. The structure of chiral dopant was also found to affect the enhanced effect significantly. The results showed a correlation between the imprinting factor and the amounts of chiral or racmetic dopant and liquid crystal monomer. In contrast, the binding properties towards AML were measured for the MIPs prepared in the presence of racmetic dopant, showing decreased imprinting effect. The molar ratio of the chiral dopant to the template was also found to be crucial to improve the imprinting factor. The best affinity was obtained on the MIPs prepared with a molar ratio of template-chiral dopant of 1:1. The lowest ratio of template-chiral dopant showing an effect of improving imprinting was 1: 0.125. Moreover, it was demonstrated that binding selectivity is an emergent property derived from the content of liquid crystal monomer during the preparation of MIPs containing chiral dopant. This is the first time to prepare MIC with liquid crystal monomer and chiral dopant, providing a new way for improving the imprinting effect.