Preparation Of Molecularly Imprinted Polymer Nanospheres Towards Hypericin Via Clicking Reaction

The molecularly imprinted polymer?MIP?has a good specific selectivity for the intended molecule,and is superior to the traditional adsorption resin in separation of structurally similar substances and enrichment of active components from natural products.Due to the limitation of monomer structure and reaction type,several shortcomings such as long time required to complete polymerization,irregular structure of polymer particles and the unevenness of recognition sites remain,which directly affect the imprinting performance.In this thesis,MIP nanospheres with specific selectivity towards hypericin,a natural compound with broad potentials as medcine,were prepared via clicking polymerization.The thesis includes the following two parts:1)Firstly,molecularly imprinted polymer nanospheres?MIP-NPHs?with specific selectivity was synthesized via click reaction by using hypericin as a template molecule.The morphology and structure of the prepared nanospheres were characterized by SEM,FTIR and BET,respectivley.The effects of monomer and crosslinker structure,photoinitiator,solvent,template concentration,equivalent ratio of monomer to crosslinker on the imprinting effect of the MIP-NPHs were investigated to obtain the optimal conditions.The results indicated that the MIP-NPHs prepared under the optimal conditions,i.e.,1?3,5-diethynylpyridine,0.1 mmol?as monomer and 5?trimethylolpropane tris?3-mercaptopropionate?,0.1 mmol?as crosslinker,the concentration of the photoinitiator with 4.0 mg mL^-1,acetone/acetonitrile with a ratio of3:1?v/v?,the concentration of hypericin with 2.5 mg mL^-1and the ratio of monomer/crosslinker as 4:3?eqv.?,have a good specific adsorption(3.04 mg g^-1).In addition,the MIP-NPHs so-prepared showed good reusability within 5 recycles.2)Based on the above results,core-shell structural molecularly imprinted polymer nanospheres towards hypericin was fabricated with the optimal conditions by using Fe₃O₄magnetic nanospheres as cores?Fe₃O₄@MIPs?.The morphology and structure of Fe₃O₄@MIPs were characterized by SEM,FTIR and BET,respectively.The results showed that the specific surface area of Fe₃O₄@MIPs was higher than that of MIP-NPHs,which led to a higher adsorption capacity towards hypericin(3.43 mg g^-1).In addition,Fe₃O₄@MIPs displayed the characteristics of fast mass transfer rate,uniform recognition sites,easy separation,and good reusability,and may be used for recognition or enrichment of hypericin.