An in-vivo plasmapheresis and/or in-vivo ultrafiltration membrane comprises a plurality of elongated hollow fibers each fiber having an interior lumen extending along the fiber length, the fiber wall having a plurality of zones between the inner and outer wall surfaces, each of the zones having a mass...http://www.google.com/patents/US6802820?utm_source=gb-gplus-sharePatent US6802820 - Specialized hollow fiber membranes for in-vivo plasmapheresis and ultrafiltration
