Solvent-resistant P84-based mixed matrix membrane adsorbers

Abstract

This work reports new mixed matrix hollow fiber membranes for adsorption of biomolecules from organic solvents. The membranes are composed of polyimide P84, the porous matrix forming polymer, and cation exchange particles incorporated in this matrix. These macroporous membranes, having homogenous structure with a uniform distribution of particles, are crosslinked with ethylene diamine (EDA) and they are therefore resistant in organic solvents such as dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP). The crosslinked P84 membranes have high static adsorption capacity for bovine serum albumin (BSA) (125.3 mg BSA/g particles) and lysozyme (Lys) (139.2 mg Lys/g particles) in aqueous systems due to the electrostatic interactions between the proteins and the charged particles. The adsorption capacity of lysozyme in DMSO and cholesterol in NMP is much lower than in the aqueous systems, because it is mainly only due to the hydrophobic interactions and it is influenced by membrane swelling in these solvents. Furthermore the biomolecules seem to have better accessibility to the particles in the membrane in comparison to particle suspension due to particle aggregation in the later case. The relative ease of preparation of these crosslinked P84 membranes may open new perspectives in processing and isolation of biomolecules from non-aqueous media.