Silane-Modified Magnetic Beads:Application to Immunoglobulin G Separation

摘要

The magnetic poly(2-hydroxyethyl methacrylate ethylene glycol dimethacrylate)[m-poly(HEMA-EGDMA)] beads(150-250-mu n diameter in spherical form)were prepared by a radical suspension polymerization technique.The pseudo-specific ligand,reactive imidazole containing 3-(2-imidazoline-1-yl)propyl(triethoxysilane)(IMEO)was selected as a silanization agent.IMEO was covalently immobilized onto the magnetic beads.IMEO-immobilized m-poly(HEMA-EGDMA)beads were used for the affinity adsorption of immunoglobulin-G(IgG)from aqueous solutions and human plasma.To evaluate the degree of IMEO attachment,the m-poly(HEMA-EGDMA)beads were subjected to Si analysis by using flame atomizer atomic absorption spectrometer,and it was estimated as 36.6 mg IMEO/g of polymer.The nonspecific IgG adsorption onto the plain m-poly(HEMA-EGDMA)beads was very low(about 0.4 mg/g).Higher adsorption values(up to 55 mg/g)were obtained when the m-poly(HEMA-EGDMA)/IMEO beads were used from both aqueous solutions and human plasma.The maximum IgG adsorption on the m-poly(HEMA-EGDMA)-IMEO beads was observed at pH 7.0.The IgG molecules could be repeatedly adsorbed and desorbed with m-poly(HEMA-EGDMA)-IMEO beads without noticeable loss in the IgG adsorption capacity.The adsorption capacity from human plasma in magnetically stabilized fluidized bed decreased drastically from 78.9 to 19.6 mg/g with the increase of the flow rate from 0.2 to 3.5 mL/min.