Abstract
Membrane-based affinity chromatography has advantages over conventional bead-based chromatography for the following two reasons : (1) the module charged with hollow fibers requires a much lower operating pressure than a bead-packed bed ; and (2) as the biomolecule can be transported by convection to the ligand immobilized on the inner surface of the microporous membrane, faster adsorption onto the affinity membrane can be attained. Hollow-fiber affinity membranes containing phenylalanine and tryptophan as ligands were prepared by the radiation-induced grafting of glycidyl methacrylate onto a porous polyethylene hollow fiber, followed by coupling of the epoxide group produced with Phe and Trp. The remaining epoxide group is quantitatively converted into a diol group. The diol group renders the polymer surface hydrophilic and prevents nonselective adsorption. To evaluate the adsorption behavior of the membrane, the gamma-globulin-containing buffer solution was permeated from the inside to the outside of the Trp-containing hollow-fiber affinity membrane. The breakthrough curves as a function of effluent volume coincided irrespective of the flow-rate, i. e., the residence time of the solution across the membrane, as a result of negligible diffusional mass transfer resistance.
