Patent ID: 8123940
Filing Date: 2012-02-28
Classification: A61M

Abstract:
1. A filtration unit for the selective elimination of a target substance from a biological fluid comprising an external envelope comprising at least one inlet orifice and at least one outlet orifice between which the biological fluid to be filtered flows in one direction, wherein the external envelope encloses a filtering medium comprising, stacked from upstream to downstream: an upstream structure for eliminating at least the target substance comprising a stack of two or more layers that are arranged to allow the flow of fluid through the layers in one direction comprising a non-woven material having pores with a first mean diameter, and particles interposed between at least some of the layers so as to form at least one sandwich, wherein the particles have an affinity for the target substance and a second mean diameter that is greater than the first mean diameter, and wherein at least two layers are welded together at their periphery and at a plurality of separate welding points so as to retain the distribution of at least a plurality of the particles interposed between the layers; and a downstream structure for retaining the particles comprising at least one layer of porous material having pores with a third mean diameter, wherein the third mean diameter is less than or equal to the first mean diameter.