A brush-type microbial-cell-capturing polymeric material was prepared by radiation-induced grafting of an epoxy-group-containing monomer, glycidyl-methacrylate (GMA), onto a polyethylene-based fiber. The epoxy ring (EO) of GMA was opened with different degrees of introduction of diethylamine (DEA). The residual epoxy group was hydrophilized by ethanolamine (EA). The prepared DEA membranes with coexisting EO or EA groups were tested for their ability to capture Staphylococcus aureus and Escherichia coil cells. The DEA membrane (2.7 mol/kg of product of DEA group density) with coexisting EO groups (DEA-EO membrane) exhibited good S. aureus-cell-capturing ability with a capturing rate constant of 1.82 x 10(-6) m/s, whereas the DEA membrane with coexisting EA groups (DEA-EA membrane) retarded capturing abilities for both S. aureus and E. coil cells.