Gas transfer and blood compatibility of asymmetric polyimide hollow fiber

We have fabricated an asymmetric polyimide hollow fiber for use as a membrane oxygenator. A dry/wet phase inversion process has been applied to a spinning process to prepare the hollow fiber. The fiber structure consisted of a complete defect-free skin layer and a porous substructure characterized by the presence of an open-cell structure and macrovoids. The outer diameter was 480 microm with a wall thickness of 50 microm. Transfer rates of O2 and CO2 in the asymmetric polyimide fiber were 2.3 x 10(-5) and 1.1 x 10(-4) (cm3 (STP)/(cm2 s cmHg)), respectively, which were four times higher than those measured in the polydimethylsiloxane (PDMS) fiber of the presently-available membrane oxygenator. The (QO2/QN2) selectivity of the polyimide fiber was 4.9, indicating that the surface skin layer is essentially defect-free. The blood compatibility of the polyimide hollow fiber has been evaluated in vitro and in vivo. The polyimide had an excellent blood compatibility when compared with PDMS.