Study On Novel Synthetic Methods Of Molecularly ImprintedPolymers And Their Application In The Molecular Recognition

Molecular imprinting is recognized as a powerful technique to synthesize polymer-type artificial receptors. In this technique, functional monomers and crosslinkers are polymerized in the presence of a template molecule, which is followed by the template removal from the resultant polymer network to leave a template-fitted cavity. The functional monomers used are expected to be complementary to the functional groups of the template molecule through hydrogen bonding, charge interaction, complexing and so on, to form a preorganized supramolecular assembly before polymerization. Consequently, the imprinted polymers exhibit the template-selective binding ability. The molecularly imprinted polymers have been used as chromatographic separation materials, solid phase extractors, catalysts, chemosensors as well as artificial antibodies.By reaction of 7-chloroethyl-theophylline with aminopropylsilanized silica gel we synthesized a 7-chloroethyl-theophylline-immobilized silica gel as template molecule and prepared a molecularly imprinted polymer (MIP-Si), which had special recognition sites to 7-chloroethyl-theophylline. A conventional molecularly imprinted polymer (MIP) using 7-chloroethyl-theophylline as template was also prepared for comparison. By UV-vis spectrum and scanning electronic microscope we compared the surface configurations and binding abilities to 7-chloroethyl-theophylline and its structural analogs with the two polymers MIP-Si and MIP. Result revealed that the MIP-Si shows much higher binding speed and much more binding capacity than the MIP does.Using Z-L-phenylalanine as template and acrylamide as functional monomer, we also prepared molecularly imprinted polymer film by grafting radical initiator, 4,4'-azobis(4-cyanopentanoic acid), on the 3-glycidoxy propyl dimethyl ethoxysilane modified silica gel particles. Such particularly prepared imprinted polymers are expected to be used in a microchip channel for on-line separation and laser induced fluorescence determination of amino acid derivatives. A mini-scale synthetic procedure was also used for detail study on the synthetic conditions of molecularly imprinted polymers.