Surface characterization of polysulfone membranes modified by DNA immobilization

Modification of a polysulfone (PSf) membrane was carried out by immobilizing single-strand DNA onto its surface. The immobilized DNA was found to be stable in water and in normal saline solution. The hydrophilicity increased when DNA was immobilized onto the membranes by UV-irradiation. The amount of protein adsorbed onto the surface of the membranes after DNA immobilization had decreased, but it was not obvious, due to the interaction between the DNA and protein. To study the effect of the surface properties on the amount of immobilized DNA and protein adsorption, PSf membranes with different surface properties were prepared. It was found that the PSf membranes exhibit significant differences depending on their surface properties and intrinsic properties due to different fabrication processes. The amount of immobilized DNA and protein adsorption were higher for the porous membranes prepared by immersing the polymer solution into a precipitation bath compared to the smooth membrane prepared by the solvent evaporation process. These results showed that insoluble DNA can be immobilized onto the surface of the PSf membrane, and the DNA-immobilized membrane prepared by UV-irradiation has the potential to be used in biomedical fields. (C) 2002 Elsevier Science B.V. All rights reserved.