Preparation of affinity membranes using polymer phase separation and azido-containing surfactants

We propose a novel approach to prepare affinity membranes using azido-containing surfactants and click chemistry. Porous polymeric membranes were prepared using cellulose acetate via polymer phase separation in the presence of azido-containing surfactants. Thermally induced phase separation and nonsolvent-induced phase separation were used for membrane preparation. The azido groups displayed on the membrane surfaces were conjugated with nitrilotriacetic acid via Huisgen 1,3-dipolar cycloaddition to prepare membranes that displayed affinity toward a hexahistidine-tagged protein. Two types of phase separation successfully produced porous membranes with different microstructures but showed similar separation performances. In place of nitrilotriacetic acid, D-Ala-D-Ala was conjugated to the surface of the azido-functionalized membrane. The membranes functionalized with D-Ala-D-Ala showed high affinity toward vancomycin. The present approach leads to facile surface functionalization of polymeric materials and produces affinity membranes displaying various types of ligands on their surfaces.