title: Protein binding to amphoteric polymer brushes grafted onto a porous hollow-fiber membrane.
abstract: Three kinds of ampholites, i.e., 3-aminopropionic acid (NH2C2H4COOH), (2-aminoethyl)phosphonic acid (NH2C2H4PO3H2), and 2-aminoethane-1-sulfonic acid (NH2C2H4SO3H), were introduced into an epoxy group-containing polymer brush grafted onto a porous hollow-fiber membrane with a porosity of 70% and pore size of 0.36 microm. The amphoteric group density of the hollow-fiber ranged from 0.50 to 0.72 mmol/g. Three kinds of proteins, i.e., lactoferrin (Lf), cytochrome c (Cyt c), and lysozyme (Ly), were captured by the amphoteric polymer brush during the permeation of the protein solution across the ampholite-immobilized porous hollow-fiber membrane. Multilayer binding of the protein to the amphoteric polymer brush, with a degree of multilayer binding of 3.3, 8.6, and 15 for Lf, Cyt c, and Ly, respectively, with the (2-aminoethyl)phosphonic acid-immobilized porous hollow-fiber membrane, was demonstrated with a negligible diffusional mass-transfer resistance of the protein to the ampholite immobilized. The 2-aminoethane-1-sulfonic acid-immobilized porous hollow-fiber membrane exhibited the lowest initial flux of the protein solution, 0.41 m/h at a transmembrane pressure of 0.1 MPa and 298 K, and the highest equilibrium binding capacity of the protein, e.g., 130 mg/g for lysozyme. Extension and shrinkage of the amphoteric polymer brushes were observed during the binding and elution of the proteins.
authors.affiliation: Department of Applied Chemistry and Biotechnology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Iwanade
authors.forename: Daisuke
authors.initials: D
authors.lastname: Umeno
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Saito
authors.forename: Takanobu
authors.initials: T
authors.lastname: Sugo
mesh_terms: D000327:Adsorption; D008567:Membranes, Artificial; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D011485:Protein Binding
chemical_list: D008567:Membranes, Artificial; D011108:Polymers