Designing and preparation of novel alkaloid-imprinted membrane with grafting type and its molecular recognition characteristic and permselectivity.

A novel polysulfone-based molecularly imprinted membrane (MIM) with graft type (designated as GMIM) was successfully prepared by a combination of film-forming method of immersion-precipitation phase transformation with molecule surface-imprinting technique. The porous asymmetry membrane of chloromethylated polysulfone (CMPSF) was first prepared by a phase inversion method, and then the CMPSF membrane was amination-modified with ethanediamine as reagent, resulting aminated polysulfone membrane AMPSF, on whose surface primary amino groups were contained. Then the graft-polymerization of methacrylic acid (MAA) was realized by initiating of the surface-initiating system of -NH2/S2O8(-), obtaining the grafted membrane PSF-g-PMAA. After PSF-g-PMAA membrane adsorbed matrine, the crosslinking reaction of the grafted PMAA was allowed to be carried out with ethylene glycol diglycidyl ether (EGDE) as crosslinker, resulting in the matrine imprinted membrane with graft type, GMIM. The binding characteristics of the imprinted membrane GMIM, the permeability and separation property for matrine were investigated in depth. The experimental results show that the imprinted membrane consists of a thin imprinted layer, a thin skin layer containing channels at nanoscale and a support layer with macroporous structure. The imprinted membrane GMIM has specific recognition selectivity and excellent binding affinity for matrine, and its selectivity coefficient for matrine relative to cytisine is 4.85. More importantly, the imprinted membrane can produce good "gate effect" because of its own structure characteristic, so that it has fine permselectivity for the template, matrine molecule. The separation coefficient of the imprinted membrane GMIM for matrine relative to cytisine as a contrast reaches up to 5.9, displaying the excellent performance of a selectively permeable membrane.