The present disclosure relates to semipermeable membranes which are suitable for blood purification, e.g. by hemodialysis, which have an increased ability to remove larger molecules while at the same time effectively retaining albumin. The membranes are characterized by a molecular retention onset (MWRO) of between 9.0 kD and 14.5 kD and a molecular weight cut-off (MWCO) of between 55 kD and 130 kD as determined by dextran sieving curves and can be prepared by industrially feasible processes excluding a treatment with salt before drying. The invention therefore also relates to a process for the production of the membranes and to their use in medical applications.

Described herein is a polyamide hollow fiber membrane and methods of making and using the hollow fiber membrane. The polyamide hollow fiber membrane has an isopropanol permeability of from about 5 L/m2 h bar to about 150 L/m2 h bar and a particle rejection percentage of about 100% for particles having a nominal diameter of from about 1 nm to about 25 nm. The polyamide hollow fiber membranes described herein are particularly useful for photoresist filtration, for example.

A whole blood hollow fiber membrane filter medium is provided with a ceramic material having pores of a pore size that ensures permeability to blood plasma or serum and its molecular components while blood cells are retained. The whole blood hollow fiber membrane filter medium is used for separating blood plasma from whole blood, wherein the blood plasma preferably shows no hemolysis.

Problems that the invention is to solve is to provide a composite hollow fiber membrane being excellent in separation performance and permeation performance, having high membrane strength, and capable of being easily produced, and a method for producing the same. The present invention relates to a composite hollow fiber membrane including at least a layer (A) and a layer (B), in which the composite hollow fiber membrane has an outer diameter of 20 to 350 m and an inner diameter of 14 to 250 m, the tensile modulus of the composite hollow fiber membrane is from 1,000 to 6,500 MPa, the layer (A) contains a cellulose ester, the thickness of the layer (A) is from 0.01 to 5 m, and the open pore ratio H.sub.A of the layer (A) and the open pore ratio H.sub.B of the layer (B) satisfy H.sub.A<H.sub.B.

A hollow fiber membrane and a method of preparing the same. The hollow fiber membrane has an inner surface and an outer surface, wherein the inner surface has a zebra-stripe pattern in which a dense portion and a porous portion are alternately formed in a longitudinal direction of the hollow fiber membrane.

A blood treatment material has both the water permeability to allow removal of water from the blood and the ability to highly efficiently adsorb and remove, for example, inflammatory cells and inflammatory cytokines. The blood treatment material includes a hollow fiber membrane having a surface modified with a ligand containing an amino group(s), wherein the arithmetic mean roughness (RaA) of the blood-contacting surface of the hollow fiber membrane in the radial direction calculated by using a laser microscope is 0.10 ?m to 0.80 ?m.

Provided is a porous hollow fiber membrane made of a thermoplastic resin, wherein a membrane thickness is 0.050 mm or larger and 0.25 mm or smaller, and when a strength coefficient is defined as K=(compressive strength)/((membrane thickness)/(inside diameter/2)).sup.3, K=1.7 or more.

A fiber-reinforced porous hollow fiber membrane comprising a hollow fiber membrane and a reinforcing fiber completely or partially embedded in the hollow fiber membrane; wherein the reinforcing fiber is placed in a portion that does not exceed 90%, preferably 80%, of the thickness of the hollow fiber membrane as viewed from an inner or outer peripheral surface of the hollow fiber membrane on a side that is not a side of the porous hollow fiber membrane to come in contact with an object to be treated, and preferably at least 50 volume % of the cross section of the reinforcing fiber is embedded in the hollow fiber membrane. The obtained fiber-reinforced porous hollow fiber membrane has excellent permeability, separation performance, and mechanical properties.

The present disclosure relates to hollow fiber tangential flow filters, including hollow fiber tangential flow depth filters, for various applications, including bioprocessing and pharmaceutical applications, systems employing such filters, and methods of filtration using the same.

A filtration membrane made by a method that includes: a) selecting and preparing an organic polymer, such as a collodion; b) injecting a collodion into at least one channel of an extrusion die that also comprises an extrusion die core and at least one outlet; c) injecting an internal liquid into a hollow centering pin, the hollow centering pin comprising a channel positioned on the core of the extrusion die and also positioned at an axis of the outlet of the extrusion die; d) applying a holding film to the outlet of the extrusion die; e) unrolling the holding film onto a surface of at least one hollow fiber emerging from the outlet of the extrusion die; f) immersing the hollow fiber with the first holding film in a rinsing solution so as to obtain a flat hollow fiber filtration membrane; and ending the rinsing of the filtration membrane.